Introduction: Dr. Shao's return journey
On September 1, 2005, Xu Guanhua, Minister of Science and Technology, met with the doctoral team from Japan and the United States, represented by Dr. Shao Chunlin, in the conference room on the third floor of the Ministry of Science and Technology. This is the second time Dr. Shao has returned to China in the most recent month.
In 1986, Dr. Shao Chunlin received his Ph.D. in engineering from the Graduate School of Nagoya University, Japan. After returning to China in 1987, Shao Chunlin, who majored in optoelectronics, did not have a suitable position in China. In 1991, he returned to Japan to continue his research work. Since he began his master's degree in compound semiconductor research in 1980, Shao Chunlin has more than 20 years of experience in semiconductor optoelectronic device research and witnessed the development of Japanese optoelectronic technology as the world's leading country.
Shao Chunlin's current Nano Devices and Systems Research Center of Nagoya Institute of Technology is one of the three most important technology sources for Japanese LEDs. It is also the core equipment of the Japanese LED industry, MOCVD (organic metal chemical vapor deposition), Japan's cation (SANSO). The technical support unit, the company's MOCVD equipment currently accounts for 80% of Japan's top ten hyaluronic acid MOCVD before the prototype, basically in the research center where Shao Chunlin is located. More importantly, through the efforts of Shao Chunlin, the Nano Devices and Systems Research Center of Nagoya Institute of Technology has a group of Chinese researchers who have mastered the complete technology of growth of semiconductor epitaxial chips, optoelectronic devices and optical sensors.
On September 1, Shao Chunlin visited the main topic of Minister Xu Guanhua, which is the development plan of China's optoelectronics industry. In the middle of August, Dr. Shao Chunlin has had in-depth communication with the National Semiconductor Lighting Engineering Secretariat. Shao Chunlin introduced that in the field of LED, there are three main links: the growth, chip and package of the epitaxial wafer of the light-emitting semiconductor. At present, there are three links in the domestic market. There are still some foundations in the low-end application field, but there is still a big gap between the key links, especially the growth of the epitaxial film, and the world-class level. From the perspective of the industrial value chain, the growth of epitaxial wafers accounts for 70% of the value. High-quality epitaxial wafers have become the main constraint in the development of China's LED industry.
Professor Chen Lianghui, a well-known expert in optoelectronic semiconductors and academician of the Chinese Academy of Engineering, visited the Nano Devices and Systems Research Center of Nagoya Institute of Technology last year. In the LED field, the team with Shao Chunlin as the core is rare in the world. Dr. Shao Chunlin is also full of confidence in returning to China to upgrade the Chinese LED industry to a world-class level.
National Semiconductor Lighting Project
In fact, as early as 1907, humans discovered the phenomenon of electroluminescence of semiconductor materials, but the real commercial LED was in the 1960s. The LED at that time was made of compound semiconductor material GaAsP and emitted red light. Throughout the 1960s and 1970s, LEDs had very low luminous efficiencies and were unable to excite a very important primary color, blue light. At this stage, LEDs are mainly used in various expensive devices as signal indicators.
In the 1990s, with the invention of nitride LEDs, the luminous efficiency of LEDs has made a qualitative leap, and the important primary color blue light that constitutes white light was also invented in 1992 by Nakamura Shuji, the famous Japanese LED company Nichia. In this way, the monochromatic LED in the entire visible light field is complete, and it can satisfy various applications of monochromatic illumination.
The most significant change affecting the development of the LED industry is the invention of high-brightness white LEDs. Since the invention of white LED in 1997, experts have studied the possibility of white LED entering the general lighting field. As a light source, LED advantages are reflected in three aspects: energy saving, environmental protection and long life. LED does not rely on filament heating to emit light, energy conversion efficiency is very high, theoretically can achieve 10% energy consumption of incandescent lamps, compared to fluorescent lamps, LED can also achieve 50% energy-saving effect. China Green Lighting Project Promotion Project Office has conducted a special investigation. China's lighting power consumption is more than 300 billion degrees per year. Replace all incandescent lamps with LEDs or partially replace fluorescent lamps, saving 1/3 of lighting power, which means saving 100 billion yuan. Degree is equivalent to a total investment of more than 200 billion in the Three Gorges Project's annual power generation. This is undoubtedly of great significance to China, where energy is very tight. Similarly, the US Department of Energy has a similar forecast. By 2010, if half of the incandescent lamps in the United States were replaced by LEDs, the electricity savings would only reach $35 billion. In terms of service life, the LED is solid-packed and has a firm structure with a life of 100,000 hours, 10 times that of fluorescent lamps and 100 times that of incandescent lamps. In terms of environmental protection, LEDs are used instead of fluorescent lamps to avoid secondary pollution of mercury rupture in fluorescent tubes.
It is against this background that the United States, Japan, Europe, and South Korea have developed corresponding national semiconductor lighting plans. For example, Japan pioneered the "21st Century Lighting" program in the world in 1998, aiming to increase the energy efficiency of lighting by twice as much as conventional fluorescent lamps by using long-lived, thinner and lighter GaN high-efficiency blue and ultraviolet LED technologies, reducing CO2. The production and completion of the replacement of 50% of traditional lighting with LEDs in 2006. The budget for the entire program is 6 billion yen. From 1998-2002, the first phase of the goal of 5 billion yen has been completed. Now, Japan is implementing the second phase of the plan, and it is planned that the luminous efficiency of LEDs will reach 120 lm/W by 2010.
The Next Generation Lighting Program (NGLI), developed by the United States in 2000, was included in the Energy Act and is planned to invest $500 million from 2000-2010. The US semiconductor lighting plan will achieve such results: reduce the discharge of 258 million tons of carbon pollutants; build 133 new power plants; it is expected that by 2010, 55% of incandescent and fluorescent lamps will be replaced by semiconductor lamps, by 2025, solid state The use of lighting sources will reduce lighting power consumption by half, saving $35 billion annually; accumulating fiscal expenditures of $115 billion; forming a semiconductor lighting industry market with an annual output value of more than $50 billion; bringing high-quality numbers Millions of job opportunities.
The EU's "Rainbow Project" was launched in July 2000 to promote the use of white light-emitting diodes through EU subsidies. It is hoped that the application of semiconductor lighting will achieve high efficiency, energy saving, non-use of harmful materials, and the goal of simulating natural light.
South Korea's "GaN Semiconductor Development Plan" from 2000 to 2008, the government invested 472 million US dollars, the company invested 736 million US dollars. The research projects include white LEDs with GaN as research materials, blue and green laser diodes and high-power electronic components.
On June 17, 2003, the Ministry of Science and Technology of China led the establishment of the “National Semiconductor Lighting Project Coordination Leading Group†across departments, regions and industries, and proposed the overall policy for implementing semiconductor lighting projects in China, which was established from the coordination leading group. From the date of the end of 2005, this is the emergency start-up period for the semiconductor lighting project, and the key technology projects for semiconductor lighting industrialization will be urgently launched in the “10th Five-Year Planâ€. The national medium- and long-term science and technology development plan and the eleventh science and technology five-year plan, research and put forward the overall strategy and implementation plan for the development of China's semiconductor lighting industry. Starting from the "Eleventh Five-Year Plan" in 2006, the country will promote semiconductor lighting engineering as a major project.
At present, the Ministry of Science and Technology has approved Shanghai, Dalian, Nanchang, Xiamen and Shenzhen as industrial bases. In June of this year, Shenzhen “National Semiconductor Lighting Engineering Industrialization Base†was laid on the foundation of Guangming High-tech Park in Baoan District. The goal of the industrial base is to have more than 200 upper, middle and lower reaches and applied product companies by 2010. The income is close to 100 billion yuan and the foreign exchange earned more than 2.5 billion US dollars.
Nanchang City, approved by the Ministry of Science and Technology Industrialization Base in 2004, plans to build a “one district†(Nanchang National High-tech Industrial Development Zone) and a “one school†(Nanchang University) as the basic framework, while taking enterprises as the mainstay of investment. The municipal government allocates 6 million yuan of special funds each year to support enterprise R&D, technology public platform construction and project loan interest subsidies, and concentrates on building two national engineering technology research centers through human resources integration and innovation mechanisms. According to the goal of the base construction phase, during the “10th Five-Year Plan†and “Eleventh Five-Year Plan†period, the investment in the base enterprises will reach 1 billion yuan and 2 billion yuan respectively. By 2005 and 2010, its semiconductor luminescent materials and devices, display lighting The light source and LED lamps will reach an economic scale of 3 billion yuan and 10 billion yuan respectively.
Xiamen City, which was first approved by the Ministry of Science and Technology to become an industrialization base, will support the optoelectronic industry as a new type of industry with policies and funds. Xiamen Hi-tech Zone has decided to set up “Xiamen Photonics Incubator†to provide professional services and support to these SMEs in terms of capital, technology, talents and management with the experience and advantages of entrepreneurship incubation. The rapid growth of the enterprise. At the same time, it will accelerate the promotion of “incubation enterprises†to “incubation industries†and rapidly develop an industrial chain and industrial belt. In addition, Taiwan is the second largest LED industry base in the world, and Xiamen is one of the best destinations for Taiwanese industrial transfer. In the past two years, Taiwan's optoelectronic industry is undergoing a large-scale industrial gradient transfer to the motherland. At present, one-third of the large-scale optoelectronic enterprises in Xiamen come from Taiwan, and among the large-scale LED enterprises that have settled in the Torch High-tech Zone in Xiamen, they have come from Taiwan Mingda and move. Xiamen City has established the goal of establishing a secondary venture industry base for Taiwan's optoelectronics industry. It is estimated that by 2010, the scale of Xiamen's optoelectronics industry will reach 20 billion yuan.
Roughly calculate the goals of the five major industrial bases. By 2010, the entire Chinese LED industry will exceed 150 billion yuan.
Realistic application of LED
However, the industry consensus is that LEDs must really enter the general lighting field and need to be in 2010. At present, the key technical index of industrial production of LED - luminous efficiency is 50lm / W, higher than the typical luminous efficiency of incandescent lamps 15lm / W, less than the typical luminous efficiency of fluorescent lamps 80lm / W. Nichia, the world's leading LED manufacturer, predicts that LEDs exceeding 100lm/W will not be developed until 2008 at the earliest. Industry experts generally believe that LEDs must enter the field of daily lighting, at least to achieve a luminous efficiency of 120lm / W.
In the 60s and 70s of the last century, the LED industry was in the early stages of development. Although LEDs still need time to enter the daily lighting field, the current application fields of LEDs are very extensive.
In fact, from the perspective of the global market, the main application areas of high-brightness LEDs are still in the backlight of mobile devices, which accounts for nearly 60% of the entire market. Another major market is the automobile and signal lights. Dr. Huang Zhenchun, a postdoctoral researcher in the United States, focused on epitaxial wafer growth. In 2001, Dr. Huang returned to China to establish LED packaging company - Ao Lei Optoelectronics, and served as the company's CEO. There is also a huge application space for LEDs in China.
Huang Zhenchun said that many cities now rely on high-powered spotlights to outline buildings and consume a lot of electricity. In recent years, electricity has been strained and the city lighting project has to stop. It is entirely possible to draw out the outline of the building with LEDs. From the visual point of view, the spotlight relies on the reflection of the building, which requires high brightness, and the LED is self-illuminating, and the energy consumption will be greatly reduced under the same visual effect. More importantly, the LEDs are rich in color and can form a color pattern. Huang Zhenchun introduced Ao Lei Optoelectronics to make a landscape light for a building in Chongqing. The whole image is like a huge Sichuan opera mask. The LED packaging material is colored. It is a Facebook image during the day and a colorful Facebook image at night.
Billboards that are widely used in cities can also be partially replaced by LEDs. Today's billboards basically use inkjet and spotlight illumination. The visual effect is the effect of inkjet reflection, which requires high illumination, while LEDs do not need reflection. At present, LED landscape lighting demonstration projects have been launched in domestic cities such as Shanghai, Xiamen and Chongqing. The 2008 Beijing Olympic Games and the 2010 Shanghai World Expo will also greatly promote the application of LED in landscape lighting. According to some data, the number of lights replaced by Beijing subway lighting is about 10% per year, and the use of long-life power-saving LEDs will inevitably reduce the cost of replacement maintenance. This is undoubtedly a feasible solution for urban public lighting. It can be predicted that LEDs will be rapidly popularized in domestic landscape lighting in the next five years. The Chongqing Municipal Government plans to invest 160 million yuan in 2006 to support landscape lighting. In addition, local districts and building owners will support themselves, and the investment is expected to be around 300 million yuan. According to conservative estimates, if the city's 100 large and medium-sized cities, the average investment in landscape lighting for each city is 100 million yuan, it will have a market size of 10 billion yuan. At present, the value of LED tubes accounts for about 1/2 of the landscape products, so it is estimated that the amount of high-brightness LEDs is about 100-20 billion per year. The report of the National Semiconductor Lighting Coordination Leading Group Office at the Xiamen International Conference in April 2005 pointed out that by 2008, China's urban landscape lighting market will reach about 20 billion yuan, becoming the largest application field in the LED market.
In the last two years, the main application area of ​​LED--the growth of handheld devices is limited, but in the high-end applications such as automobiles, the market space for LEDs is growing rapidly. According to statistics, more than 80% of cars in Europe currently use LED lighting. For example, the commonly used high-position brake lights, because the LED reaction speed is an order of magnitude faster than the traditional incandescent lamp, compared with the traditional incandescent lamp can increase the reaction time of 0.3 seconds to the rear car, which can greatly reduce the occurrence of rear-end collision. At the same time, China also stipulates that cars on the expressway must follow the installation of LED fog lamps. In the field of automotive lighting, in addition to the headlights, LEDs currently do not meet the requirements of large-scale applications. Others such as instrument indicators, interior lighting, and taillights can be replaced by LEDs. The advantage of LED lights in automotive lighting is that they can be made into any shape, and the life of LED lights often exceeds the life of the car and does not need to be replaced.
Another fast-growing market is the large-screen LCD backlight. At present, Toyota Synthetic has developed a 32-inch LCD backlight. Toshiba used a 32-LED independent control mechanism on its famous U100 notebook 7.2-inch LCD screen to achieve a backlight system with a power of only 1.3W. The CCFT (Cold Cathode Fluorescent Tube) required for the same size LCD screen consumes more than 2.5W. The reduced power consumption also directly extends the battery life of the U100, enhancing the portability of the notebook. LCD TVs with LED backlights have a gamut that can exceed 100% of NTSC, reaching 105%, while traditional CCFT backlights can reach up to 78% of NTSC. The use of LEDs as backlights is expected to address the fatal shortcomings of insufficient LCD color saturation. It is still a price issue that restricts the large-scale entry of LEDs into the large-screen backlight market.
In addition, in the field of optical communications, LEDs are likely to usher in a new development climax. Ao Lei Optoelectronics, led by Huang Zhenchun, recently passed Cisco's supplier certification, providing products that are signal generators used in the field of optical communications. Huang Zhenchun introduced that the construction of the domestic intelligent building has begun. For example, Zhenjiang Hengmei Homeland is a fiber-optic home, which realizes the integration of TV, telephone and Internet. In this process, a large number of transceivers, switches, and switching devices are required. Ole Optoelectronics produces optical signal generators for Cisco. Huang Zhenchun said that it is enough for the company to eat. At present, the price of optical fiber has dropped to an acceptable range, and fiber-to-the-home and fiber-to-desktop are entirely possible. This may bring an explosive growth to LEDs.
With the development of device levels, some new applications have also been developed. It has been reported internationally that in agriculture, special wavelength ultraviolet LEDs can be used to kill insects. In the medical field, such as the treatment of cancer, special wavelength UV LEDs can be implanted into the body to target cancer cells.
In fact, China Electronic Components Association also expects that China's high-brightness LED market will grow by 50% in 2005. Chairman of Shanghai Holographic Investment Co., Ltd., who is also an investor in the preparation of Zhong Shaochun's technical consultant, said that a leading LED manufacturer like Nichia is not eager to enter the general lighting field. The capacity of the high-end market has already made them It can't be done.
Current situation in China
But China's LED industry faces a huge problem, that is, the technology level is too low. According to Huang Zhenchun, China's LED industry is just in its infancy, not only with Japan, the United States, and Europe, but also far from Japan and Taiwan.
Huang Zhenchun estimates that the domestic LED industry scale is about 10 billion yuan, while Japan's only Nichia Chemicals' sales revenue reached 2 billion US dollars last year. The domestic industry scale is equivalent to more than half of Nichia's family. At present, there are more than 10 companies in China that do LED epitaxial chips and chip packaging. The industry scale is small, and the largest is only the output value of 200 million yuan. The domestic epitaxial wafer growth technology is mainly from the United States, and is basically imported from the United States, the organic metal chemical vapor deposition (MOCVD) equipment, these equipment is not a first-class equipment in the United States. Dr. Shao Chunlin introduced that in the three stages of the growth, chip and chip packaging of the entire LED industry epitaxial wafer, the epitaxial wafer growth investment should account for 70%, and the epitaxial wafer cost should account for 70% of the packaged finished chip, and the epitaxial wafer growth. The talent of technology is lacking all over the world. Simply put, the level of epitaxial wafers determines the level of the entire LED industry.
The growth of epitaxial wafers not only requires first-class MOCVD equipment, but more importantly, 50 epitaxial wafers are grown on the substrate material, and the epitaxial wafer atomic arrangement of each layer is required to be consistent with the substrate. The relevant parameters in the production process are Thousands, debugging these parameters requires a lot of time and money. Huang Zhenchun said that Japan, the United States and other developed countries have long-term technical accumulation, which can be optimized among thousands of parameters, and China's growth process often begins with a small number of parameter changes. As far as raw materials are concerned, the organometallic chemical vapor deposition production process requires very high purity of raw materials, such as 99.9999%, 6-9, and many domestically produced raw materials do not meet this requirement. At present, there is no talent in the production of MOCVD equipment in China, not to mention the enterprise. It is difficult for the domestic LED industry to make breakthroughs in a short time.
In addition, Dr. Huang Zhenchun said that the technical level of domestic customary laboratories is compared with the level of foreign industrialization. In fact, the industrialization of the laboratory technology level will take several years. Huang Zhenchun borrowed the words of Dr. Schulte, President of the European Optical Industry Association, saying that China must now recognize the gap between the industrial technology level and the developed countries.
For example, Huang Zhenchun, the price of high-power white LED produced by Nichia Chemical is close to 50 yuan/only, the price in the United States is about 30 yuan/only, and that in Taiwan is 15 yuan/only. The price of foreign first-class manufacturers is high and often cannot be bought. Some domestic applications can only use low-priced chips. For example, in the market landscape lighting where LED is very important, the chips used by some domestic enterprises have a failure rate of 0.1%, but the LEDs used for LEDs are generally connected in series, and the whole lamp is not bright, so There are more than 10% failure rates, and there are many examples of failures in real-world applications. There are even many companies that use LED solutions to bid, but the specific implementation uses traditional lighting.
iSupply also analyzed that in the low-end LED industry, Asia, especially Chinese companies, are in the midst of fierce price competition, but the world-class companies such as Nichia, Toyota Synthetic, Cree and Osram have maintained good profits. According to reports, Nichia's 2004 pre-tax profit margin reached 56%.
Dr. Shao Chunlin introduced that among the world's leading LED companies, Nichia and United States Lumileds Lighting Company, United States Cree and Japan LED companies, want to monopolize the world's high-brightness LED market often sees the world's high-bright LED exports, Japan The United States and Taiwan account for 86% of the world's export market, and China accounts for only 3%.
However, the current status quo is rapidly changing. On the one hand, with the support of the national LED industry policy, the investment of the state, industrial bases and enterprises is growing at a high speed; on the other hand, the return of the team like Shao Chunlin will inevitably lead to the improvement of the technical level of the entire industry.
Industry outlook
The most attractive prospects for the LED industry may not be the applications currently seen. The current international consensus is that optoelectronic technology is the cutting-edge technology of the 21st century. If the dominant industries in the 21st century are ranked, the first is the optoelectronics industry, the second is the information and communication industry, and the third is the health and welfare industry.
LED is the most important optoelectronic material and component in the optoelectronics industry. It is the most active optoelectronic industry in the entire optoelectronics industry. For example, optical communication is developing towards ultra-large capacity, high-speed and all-optical networks, and ultra-large capacity DWDM. All-optical networks will become the main development trend; optical display will develop in true color, high resolution, high definition, large screen and flatness; optical storage will adopt more new technologies and new materials to develop a new generation of high Density, high-speed optical storage technology and systems; optical output into products in the direction of multi-function, high-speed, low-cost; optical device development trend is miniaturization, high reliability, multi-function, modularization and integration; Fully solidified, ultra-short wavelength, micro-machining and high reliability development, laser technology and other disciplines and application areas continue to expand; photonic computing and optical information processing industry, all-optical electronic communication industry, photonic integrated device industry, polymer Fiber optic cable industry, polymer optoelectronic device industry and photonic sensor industry, etc., all of which are not represented by LED Sub-materials and components
The scientific community predicts that by 2005, the output value of the optoelectronics industry will reach the output value of the electronics industry; by 2010, the information industry led by optoelectronic information technology will form an industry scale of 5 trillion US dollars; from 2010 to 2015, the optoelectronics industry It may replace the traditional electronics industry, become the largest industry in the 21st century, and become an important indicator to measure a country's economic development and overall national strength.
In fact, in the field of LED industry, there are also Moore's Law similar to the field of microelectronics. Agilent's former technical scientist Roland Haitz predicts that LED prices will be one-tenth of a decade and performance will increase by a factor of 20, a prediction that was later called Haitz's law. It is this prediction that brings infinite broad prospects to the future LED industry.
Link: LED small data
led
LED is the abbreviation of English light emitting diode. Its basic structure is an electroluminescent semiconductor material placed on a leaded shelf and then sealed with epoxy resin to protect the inner core. effect.
The core of the LED is a wafer consisting of a p-type semiconductor and an n-type semiconductor. There is a transition layer between the p-type semiconductor and the n-type semiconductor, called a pn junction. In some PN junctions of semiconductor materials, the injected minority carriers recombine with the majority carriers to release excess energy in the form of light, thereby directly converting electrical energy into light energy. The PN junction adds a reverse voltage, and minority carriers are difficult to inject, so they do not emit light. Currently, light-emitting semiconductor materials are mainly composed of group III-V elements, such as gallium phosphide (GaP), gallium arsenide (GaAs), gallium nitride, and the like. For the entire global industry, the technology route based on MOCVD epitaxial growth is the main technical trend in the development of GaN-based optoelectronic materials and devices. Epitaxial growth of GaN-based materials is the core technology for the development of GaN-based high-brightness LEDs and all-solid-state semiconductor white light illumination sources, and is the top priority of all key challenges.
In GaN-based optoelectronic devices, a large number of patents focus on the structural design of the illuminating region, and the purpose of the patent design is to improve the luminous efficiency of the active region.
Technical Information
Epitaxial wafer growth
The basic principle of epitaxial growth is that on a substrate substrate (mainly ruby ​​and SiC) heated to a suitable temperature, the gaseous substances In, Ga, Al, P are controlled to be transported to the surface of the substrate to grow specific. Single crystal film. At present, the LED epitaxial wafer growth technology mainly adopts an organometallic chemical vapor deposition method.
MOCVD
Metal-Organic Chemical Vapor Deposition (MOCVD), a new technology for preparing compound semiconductor single-film films proposed by Rockwell Corporation in 1968. This equipment integrates precision machinery, semiconductor materials, vacuum electronics, fluid mechanics, optics, chemistry, and computer multidisciplinary. It is a state-of-the-art optoelectronic special equipment with high degree of automation, high price, and high technology integration. It is mainly used for GaN ( The epitaxial growth of GaN-based semiconductor materials and the fabrication of blue, green or ultraviolet light-emitting diode chips are among the most promising specialized devices in the optoelectronics industry.
On September 1, 2005, Xu Guanhua, Minister of Science and Technology, met with the doctoral team from Japan and the United States, represented by Dr. Shao Chunlin, in the conference room on the third floor of the Ministry of Science and Technology. This is the second time Dr. Shao has returned to China in the most recent month.
In 1986, Dr. Shao Chunlin received his Ph.D. in engineering from the Graduate School of Nagoya University, Japan. After returning to China in 1987, Shao Chunlin, who majored in optoelectronics, did not have a suitable position in China. In 1991, he returned to Japan to continue his research work. Since he began his master's degree in compound semiconductor research in 1980, Shao Chunlin has more than 20 years of experience in semiconductor optoelectronic device research and witnessed the development of Japanese optoelectronic technology as the world's leading country.
Shao Chunlin's current Nano Devices and Systems Research Center of Nagoya Institute of Technology is one of the three most important technology sources for Japanese LEDs. It is also the core equipment of the Japanese LED industry, MOCVD (organic metal chemical vapor deposition), Japan's cation (SANSO). The technical support unit, the company's MOCVD equipment currently accounts for 80% of Japan's top ten hyaluronic acid MOCVD before the prototype, basically in the research center where Shao Chunlin is located. More importantly, through the efforts of Shao Chunlin, the Nano Devices and Systems Research Center of Nagoya Institute of Technology has a group of Chinese researchers who have mastered the complete technology of growth of semiconductor epitaxial chips, optoelectronic devices and optical sensors.
On September 1, Shao Chunlin visited the main topic of Minister Xu Guanhua, which is the development plan of China's optoelectronics industry. In the middle of August, Dr. Shao Chunlin has had in-depth communication with the National Semiconductor Lighting Engineering Secretariat. Shao Chunlin introduced that in the field of LED, there are three main links: the growth, chip and package of the epitaxial wafer of the light-emitting semiconductor. At present, there are three links in the domestic market. There are still some foundations in the low-end application field, but there is still a big gap between the key links, especially the growth of the epitaxial film, and the world-class level. From the perspective of the industrial value chain, the growth of epitaxial wafers accounts for 70% of the value. High-quality epitaxial wafers have become the main constraint in the development of China's LED industry.
Professor Chen Lianghui, a well-known expert in optoelectronic semiconductors and academician of the Chinese Academy of Engineering, visited the Nano Devices and Systems Research Center of Nagoya Institute of Technology last year. In the LED field, the team with Shao Chunlin as the core is rare in the world. Dr. Shao Chunlin is also full of confidence in returning to China to upgrade the Chinese LED industry to a world-class level.
National Semiconductor Lighting Project
In fact, as early as 1907, humans discovered the phenomenon of electroluminescence of semiconductor materials, but the real commercial LED was in the 1960s. The LED at that time was made of compound semiconductor material GaAsP and emitted red light. Throughout the 1960s and 1970s, LEDs had very low luminous efficiencies and were unable to excite a very important primary color, blue light. At this stage, LEDs are mainly used in various expensive devices as signal indicators.
In the 1990s, with the invention of nitride LEDs, the luminous efficiency of LEDs has made a qualitative leap, and the important primary color blue light that constitutes white light was also invented in 1992 by Nakamura Shuji, the famous Japanese LED company Nichia. In this way, the monochromatic LED in the entire visible light field is complete, and it can satisfy various applications of monochromatic illumination.
The most significant change affecting the development of the LED industry is the invention of high-brightness white LEDs. Since the invention of white LED in 1997, experts have studied the possibility of white LED entering the general lighting field. As a light source, LED advantages are reflected in three aspects: energy saving, environmental protection and long life. LED does not rely on filament heating to emit light, energy conversion efficiency is very high, theoretically can achieve 10% energy consumption of incandescent lamps, compared to fluorescent lamps, LED can also achieve 50% energy-saving effect. China Green Lighting Project Promotion Project Office has conducted a special investigation. China's lighting power consumption is more than 300 billion degrees per year. Replace all incandescent lamps with LEDs or partially replace fluorescent lamps, saving 1/3 of lighting power, which means saving 100 billion yuan. Degree is equivalent to a total investment of more than 200 billion in the Three Gorges Project's annual power generation. This is undoubtedly of great significance to China, where energy is very tight. Similarly, the US Department of Energy has a similar forecast. By 2010, if half of the incandescent lamps in the United States were replaced by LEDs, the electricity savings would only reach $35 billion. In terms of service life, the LED is solid-packed and has a firm structure with a life of 100,000 hours, 10 times that of fluorescent lamps and 100 times that of incandescent lamps. In terms of environmental protection, LEDs are used instead of fluorescent lamps to avoid secondary pollution of mercury rupture in fluorescent tubes.
It is against this background that the United States, Japan, Europe, and South Korea have developed corresponding national semiconductor lighting plans. For example, Japan pioneered the "21st Century Lighting" program in the world in 1998, aiming to increase the energy efficiency of lighting by twice as much as conventional fluorescent lamps by using long-lived, thinner and lighter GaN high-efficiency blue and ultraviolet LED technologies, reducing CO2. The production and completion of the replacement of 50% of traditional lighting with LEDs in 2006. The budget for the entire program is 6 billion yen. From 1998-2002, the first phase of the goal of 5 billion yen has been completed. Now, Japan is implementing the second phase of the plan, and it is planned that the luminous efficiency of LEDs will reach 120 lm/W by 2010.
The Next Generation Lighting Program (NGLI), developed by the United States in 2000, was included in the Energy Act and is planned to invest $500 million from 2000-2010. The US semiconductor lighting plan will achieve such results: reduce the discharge of 258 million tons of carbon pollutants; build 133 new power plants; it is expected that by 2010, 55% of incandescent and fluorescent lamps will be replaced by semiconductor lamps, by 2025, solid state The use of lighting sources will reduce lighting power consumption by half, saving $35 billion annually; accumulating fiscal expenditures of $115 billion; forming a semiconductor lighting industry market with an annual output value of more than $50 billion; bringing high-quality numbers Millions of job opportunities.
The EU's "Rainbow Project" was launched in July 2000 to promote the use of white light-emitting diodes through EU subsidies. It is hoped that the application of semiconductor lighting will achieve high efficiency, energy saving, non-use of harmful materials, and the goal of simulating natural light.
South Korea's "GaN Semiconductor Development Plan" from 2000 to 2008, the government invested 472 million US dollars, the company invested 736 million US dollars. The research projects include white LEDs with GaN as research materials, blue and green laser diodes and high-power electronic components.
On June 17, 2003, the Ministry of Science and Technology of China led the establishment of the “National Semiconductor Lighting Project Coordination Leading Group†across departments, regions and industries, and proposed the overall policy for implementing semiconductor lighting projects in China, which was established from the coordination leading group. From the date of the end of 2005, this is the emergency start-up period for the semiconductor lighting project, and the key technology projects for semiconductor lighting industrialization will be urgently launched in the “10th Five-Year Planâ€. The national medium- and long-term science and technology development plan and the eleventh science and technology five-year plan, research and put forward the overall strategy and implementation plan for the development of China's semiconductor lighting industry. Starting from the "Eleventh Five-Year Plan" in 2006, the country will promote semiconductor lighting engineering as a major project.
At present, the Ministry of Science and Technology has approved Shanghai, Dalian, Nanchang, Xiamen and Shenzhen as industrial bases. In June of this year, Shenzhen “National Semiconductor Lighting Engineering Industrialization Base†was laid on the foundation of Guangming High-tech Park in Baoan District. The goal of the industrial base is to have more than 200 upper, middle and lower reaches and applied product companies by 2010. The income is close to 100 billion yuan and the foreign exchange earned more than 2.5 billion US dollars.
Nanchang City, approved by the Ministry of Science and Technology Industrialization Base in 2004, plans to build a “one district†(Nanchang National High-tech Industrial Development Zone) and a “one school†(Nanchang University) as the basic framework, while taking enterprises as the mainstay of investment. The municipal government allocates 6 million yuan of special funds each year to support enterprise R&D, technology public platform construction and project loan interest subsidies, and concentrates on building two national engineering technology research centers through human resources integration and innovation mechanisms. According to the goal of the base construction phase, during the “10th Five-Year Plan†and “Eleventh Five-Year Plan†period, the investment in the base enterprises will reach 1 billion yuan and 2 billion yuan respectively. By 2005 and 2010, its semiconductor luminescent materials and devices, display lighting The light source and LED lamps will reach an economic scale of 3 billion yuan and 10 billion yuan respectively.
Xiamen City, which was first approved by the Ministry of Science and Technology to become an industrialization base, will support the optoelectronic industry as a new type of industry with policies and funds. Xiamen Hi-tech Zone has decided to set up “Xiamen Photonics Incubator†to provide professional services and support to these SMEs in terms of capital, technology, talents and management with the experience and advantages of entrepreneurship incubation. The rapid growth of the enterprise. At the same time, it will accelerate the promotion of “incubation enterprises†to “incubation industries†and rapidly develop an industrial chain and industrial belt. In addition, Taiwan is the second largest LED industry base in the world, and Xiamen is one of the best destinations for Taiwanese industrial transfer. In the past two years, Taiwan's optoelectronic industry is undergoing a large-scale industrial gradient transfer to the motherland. At present, one-third of the large-scale optoelectronic enterprises in Xiamen come from Taiwan, and among the large-scale LED enterprises that have settled in the Torch High-tech Zone in Xiamen, they have come from Taiwan Mingda and move. Xiamen City has established the goal of establishing a secondary venture industry base for Taiwan's optoelectronics industry. It is estimated that by 2010, the scale of Xiamen's optoelectronics industry will reach 20 billion yuan.
Roughly calculate the goals of the five major industrial bases. By 2010, the entire Chinese LED industry will exceed 150 billion yuan.
Realistic application of LED
However, the industry consensus is that LEDs must really enter the general lighting field and need to be in 2010. At present, the key technical index of industrial production of LED - luminous efficiency is 50lm / W, higher than the typical luminous efficiency of incandescent lamps 15lm / W, less than the typical luminous efficiency of fluorescent lamps 80lm / W. Nichia, the world's leading LED manufacturer, predicts that LEDs exceeding 100lm/W will not be developed until 2008 at the earliest. Industry experts generally believe that LEDs must enter the field of daily lighting, at least to achieve a luminous efficiency of 120lm / W.
In the 60s and 70s of the last century, the LED industry was in the early stages of development. Although LEDs still need time to enter the daily lighting field, the current application fields of LEDs are very extensive.
In fact, from the perspective of the global market, the main application areas of high-brightness LEDs are still in the backlight of mobile devices, which accounts for nearly 60% of the entire market. Another major market is the automobile and signal lights. Dr. Huang Zhenchun, a postdoctoral researcher in the United States, focused on epitaxial wafer growth. In 2001, Dr. Huang returned to China to establish LED packaging company - Ao Lei Optoelectronics, and served as the company's CEO. There is also a huge application space for LEDs in China.
Huang Zhenchun said that many cities now rely on high-powered spotlights to outline buildings and consume a lot of electricity. In recent years, electricity has been strained and the city lighting project has to stop. It is entirely possible to draw out the outline of the building with LEDs. From the visual point of view, the spotlight relies on the reflection of the building, which requires high brightness, and the LED is self-illuminating, and the energy consumption will be greatly reduced under the same visual effect. More importantly, the LEDs are rich in color and can form a color pattern. Huang Zhenchun introduced Ao Lei Optoelectronics to make a landscape light for a building in Chongqing. The whole image is like a huge Sichuan opera mask. The LED packaging material is colored. It is a Facebook image during the day and a colorful Facebook image at night.
Billboards that are widely used in cities can also be partially replaced by LEDs. Today's billboards basically use inkjet and spotlight illumination. The visual effect is the effect of inkjet reflection, which requires high illumination, while LEDs do not need reflection. At present, LED landscape lighting demonstration projects have been launched in domestic cities such as Shanghai, Xiamen and Chongqing. The 2008 Beijing Olympic Games and the 2010 Shanghai World Expo will also greatly promote the application of LED in landscape lighting. According to some data, the number of lights replaced by Beijing subway lighting is about 10% per year, and the use of long-life power-saving LEDs will inevitably reduce the cost of replacement maintenance. This is undoubtedly a feasible solution for urban public lighting. It can be predicted that LEDs will be rapidly popularized in domestic landscape lighting in the next five years. The Chongqing Municipal Government plans to invest 160 million yuan in 2006 to support landscape lighting. In addition, local districts and building owners will support themselves, and the investment is expected to be around 300 million yuan. According to conservative estimates, if the city's 100 large and medium-sized cities, the average investment in landscape lighting for each city is 100 million yuan, it will have a market size of 10 billion yuan. At present, the value of LED tubes accounts for about 1/2 of the landscape products, so it is estimated that the amount of high-brightness LEDs is about 100-20 billion per year. The report of the National Semiconductor Lighting Coordination Leading Group Office at the Xiamen International Conference in April 2005 pointed out that by 2008, China's urban landscape lighting market will reach about 20 billion yuan, becoming the largest application field in the LED market.
In the last two years, the main application area of ​​LED--the growth of handheld devices is limited, but in the high-end applications such as automobiles, the market space for LEDs is growing rapidly. According to statistics, more than 80% of cars in Europe currently use LED lighting. For example, the commonly used high-position brake lights, because the LED reaction speed is an order of magnitude faster than the traditional incandescent lamp, compared with the traditional incandescent lamp can increase the reaction time of 0.3 seconds to the rear car, which can greatly reduce the occurrence of rear-end collision. At the same time, China also stipulates that cars on the expressway must follow the installation of LED fog lamps. In the field of automotive lighting, in addition to the headlights, LEDs currently do not meet the requirements of large-scale applications. Others such as instrument indicators, interior lighting, and taillights can be replaced by LEDs. The advantage of LED lights in automotive lighting is that they can be made into any shape, and the life of LED lights often exceeds the life of the car and does not need to be replaced.
Another fast-growing market is the large-screen LCD backlight. At present, Toyota Synthetic has developed a 32-inch LCD backlight. Toshiba used a 32-LED independent control mechanism on its famous U100 notebook 7.2-inch LCD screen to achieve a backlight system with a power of only 1.3W. The CCFT (Cold Cathode Fluorescent Tube) required for the same size LCD screen consumes more than 2.5W. The reduced power consumption also directly extends the battery life of the U100, enhancing the portability of the notebook. LCD TVs with LED backlights have a gamut that can exceed 100% of NTSC, reaching 105%, while traditional CCFT backlights can reach up to 78% of NTSC. The use of LEDs as backlights is expected to address the fatal shortcomings of insufficient LCD color saturation. It is still a price issue that restricts the large-scale entry of LEDs into the large-screen backlight market.
In addition, in the field of optical communications, LEDs are likely to usher in a new development climax. Ao Lei Optoelectronics, led by Huang Zhenchun, recently passed Cisco's supplier certification, providing products that are signal generators used in the field of optical communications. Huang Zhenchun introduced that the construction of the domestic intelligent building has begun. For example, Zhenjiang Hengmei Homeland is a fiber-optic home, which realizes the integration of TV, telephone and Internet. In this process, a large number of transceivers, switches, and switching devices are required. Ole Optoelectronics produces optical signal generators for Cisco. Huang Zhenchun said that it is enough for the company to eat. At present, the price of optical fiber has dropped to an acceptable range, and fiber-to-the-home and fiber-to-desktop are entirely possible. This may bring an explosive growth to LEDs.
With the development of device levels, some new applications have also been developed. It has been reported internationally that in agriculture, special wavelength ultraviolet LEDs can be used to kill insects. In the medical field, such as the treatment of cancer, special wavelength UV LEDs can be implanted into the body to target cancer cells.
In fact, China Electronic Components Association also expects that China's high-brightness LED market will grow by 50% in 2005. Chairman of Shanghai Holographic Investment Co., Ltd., who is also an investor in the preparation of Zhong Shaochun's technical consultant, said that a leading LED manufacturer like Nichia is not eager to enter the general lighting field. The capacity of the high-end market has already made them It can't be done.
Current situation in China
But China's LED industry faces a huge problem, that is, the technology level is too low. According to Huang Zhenchun, China's LED industry is just in its infancy, not only with Japan, the United States, and Europe, but also far from Japan and Taiwan.
Huang Zhenchun estimates that the domestic LED industry scale is about 10 billion yuan, while Japan's only Nichia Chemicals' sales revenue reached 2 billion US dollars last year. The domestic industry scale is equivalent to more than half of Nichia's family. At present, there are more than 10 companies in China that do LED epitaxial chips and chip packaging. The industry scale is small, and the largest is only the output value of 200 million yuan. The domestic epitaxial wafer growth technology is mainly from the United States, and is basically imported from the United States, the organic metal chemical vapor deposition (MOCVD) equipment, these equipment is not a first-class equipment in the United States. Dr. Shao Chunlin introduced that in the three stages of the growth, chip and chip packaging of the entire LED industry epitaxial wafer, the epitaxial wafer growth investment should account for 70%, and the epitaxial wafer cost should account for 70% of the packaged finished chip, and the epitaxial wafer growth. The talent of technology is lacking all over the world. Simply put, the level of epitaxial wafers determines the level of the entire LED industry.
The growth of epitaxial wafers not only requires first-class MOCVD equipment, but more importantly, 50 epitaxial wafers are grown on the substrate material, and the epitaxial wafer atomic arrangement of each layer is required to be consistent with the substrate. The relevant parameters in the production process are Thousands, debugging these parameters requires a lot of time and money. Huang Zhenchun said that Japan, the United States and other developed countries have long-term technical accumulation, which can be optimized among thousands of parameters, and China's growth process often begins with a small number of parameter changes. As far as raw materials are concerned, the organometallic chemical vapor deposition production process requires very high purity of raw materials, such as 99.9999%, 6-9, and many domestically produced raw materials do not meet this requirement. At present, there is no talent in the production of MOCVD equipment in China, not to mention the enterprise. It is difficult for the domestic LED industry to make breakthroughs in a short time.
In addition, Dr. Huang Zhenchun said that the technical level of domestic customary laboratories is compared with the level of foreign industrialization. In fact, the industrialization of the laboratory technology level will take several years. Huang Zhenchun borrowed the words of Dr. Schulte, President of the European Optical Industry Association, saying that China must now recognize the gap between the industrial technology level and the developed countries.
For example, Huang Zhenchun, the price of high-power white LED produced by Nichia Chemical is close to 50 yuan/only, the price in the United States is about 30 yuan/only, and that in Taiwan is 15 yuan/only. The price of foreign first-class manufacturers is high and often cannot be bought. Some domestic applications can only use low-priced chips. For example, in the market landscape lighting where LED is very important, the chips used by some domestic enterprises have a failure rate of 0.1%, but the LEDs used for LEDs are generally connected in series, and the whole lamp is not bright, so There are more than 10% failure rates, and there are many examples of failures in real-world applications. There are even many companies that use LED solutions to bid, but the specific implementation uses traditional lighting.
iSupply also analyzed that in the low-end LED industry, Asia, especially Chinese companies, are in the midst of fierce price competition, but the world-class companies such as Nichia, Toyota Synthetic, Cree and Osram have maintained good profits. According to reports, Nichia's 2004 pre-tax profit margin reached 56%.
Dr. Shao Chunlin introduced that among the world's leading LED companies, Nichia and United States Lumileds Lighting Company, United States Cree and Japan LED companies, want to monopolize the world's high-brightness LED market often sees the world's high-bright LED exports, Japan The United States and Taiwan account for 86% of the world's export market, and China accounts for only 3%.
However, the current status quo is rapidly changing. On the one hand, with the support of the national LED industry policy, the investment of the state, industrial bases and enterprises is growing at a high speed; on the other hand, the return of the team like Shao Chunlin will inevitably lead to the improvement of the technical level of the entire industry.
Industry outlook
The most attractive prospects for the LED industry may not be the applications currently seen. The current international consensus is that optoelectronic technology is the cutting-edge technology of the 21st century. If the dominant industries in the 21st century are ranked, the first is the optoelectronics industry, the second is the information and communication industry, and the third is the health and welfare industry.
LED is the most important optoelectronic material and component in the optoelectronics industry. It is the most active optoelectronic industry in the entire optoelectronics industry. For example, optical communication is developing towards ultra-large capacity, high-speed and all-optical networks, and ultra-large capacity DWDM. All-optical networks will become the main development trend; optical display will develop in true color, high resolution, high definition, large screen and flatness; optical storage will adopt more new technologies and new materials to develop a new generation of high Density, high-speed optical storage technology and systems; optical output into products in the direction of multi-function, high-speed, low-cost; optical device development trend is miniaturization, high reliability, multi-function, modularization and integration; Fully solidified, ultra-short wavelength, micro-machining and high reliability development, laser technology and other disciplines and application areas continue to expand; photonic computing and optical information processing industry, all-optical electronic communication industry, photonic integrated device industry, polymer Fiber optic cable industry, polymer optoelectronic device industry and photonic sensor industry, etc., all of which are not represented by LED Sub-materials and components
The scientific community predicts that by 2005, the output value of the optoelectronics industry will reach the output value of the electronics industry; by 2010, the information industry led by optoelectronic information technology will form an industry scale of 5 trillion US dollars; from 2010 to 2015, the optoelectronics industry It may replace the traditional electronics industry, become the largest industry in the 21st century, and become an important indicator to measure a country's economic development and overall national strength.
In fact, in the field of LED industry, there are also Moore's Law similar to the field of microelectronics. Agilent's former technical scientist Roland Haitz predicts that LED prices will be one-tenth of a decade and performance will increase by a factor of 20, a prediction that was later called Haitz's law. It is this prediction that brings infinite broad prospects to the future LED industry.
Link: LED small data
led
LED is the abbreviation of English light emitting diode. Its basic structure is an electroluminescent semiconductor material placed on a leaded shelf and then sealed with epoxy resin to protect the inner core. effect.
The core of the LED is a wafer consisting of a p-type semiconductor and an n-type semiconductor. There is a transition layer between the p-type semiconductor and the n-type semiconductor, called a pn junction. In some PN junctions of semiconductor materials, the injected minority carriers recombine with the majority carriers to release excess energy in the form of light, thereby directly converting electrical energy into light energy. The PN junction adds a reverse voltage, and minority carriers are difficult to inject, so they do not emit light. Currently, light-emitting semiconductor materials are mainly composed of group III-V elements, such as gallium phosphide (GaP), gallium arsenide (GaAs), gallium nitride, and the like. For the entire global industry, the technology route based on MOCVD epitaxial growth is the main technical trend in the development of GaN-based optoelectronic materials and devices. Epitaxial growth of GaN-based materials is the core technology for the development of GaN-based high-brightness LEDs and all-solid-state semiconductor white light illumination sources, and is the top priority of all key challenges.
In GaN-based optoelectronic devices, a large number of patents focus on the structural design of the illuminating region, and the purpose of the patent design is to improve the luminous efficiency of the active region.
Technical Information
Epitaxial wafer growth
The basic principle of epitaxial growth is that on a substrate substrate (mainly ruby ​​and SiC) heated to a suitable temperature, the gaseous substances In, Ga, Al, P are controlled to be transported to the surface of the substrate to grow specific. Single crystal film. At present, the LED epitaxial wafer growth technology mainly adopts an organometallic chemical vapor deposition method.
MOCVD
Metal-Organic Chemical Vapor Deposition (MOCVD), a new technology for preparing compound semiconductor single-film films proposed by Rockwell Corporation in 1968. This equipment integrates precision machinery, semiconductor materials, vacuum electronics, fluid mechanics, optics, chemistry, and computer multidisciplinary. It is a state-of-the-art optoelectronic special equipment with high degree of automation, high price, and high technology integration. It is mainly used for GaN ( The epitaxial growth of GaN-based semiconductor materials and the fabrication of blue, green or ultraviolet light-emitting diode chips are among the most promising specialized devices in the optoelectronics industry.
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