The rapid development of semiconductor lighting technology market prospects

The development of semiconductor lighting technology is beyond the industry's expectations. Global LED market is developing steadily. China is a big country of traditional lighting source and lamp production, and it has a great advantage in the field of semiconductor lighting.

In 1963 February, the inventor of the LED N.Holonyak view published in the American Journal of "reader's Digest", said that LED will develop into practical white light, and make clear the prophecy: "the future is a light alloy pencil tip size, it is practical and not easily broken, never burned. Compared with today's general bulb, the conversion efficiency of at least 10 times higher. "

Rapid progress of LED Technology

Today, LED epitaxial technology, chip manufacturing technology and packaging technology have made considerable progress, Holonyak's prophecy is a step by step to become a reality.

The quality of LED epitaxial materials, largely with the substrate and epitaxial lattice matching degree, after years of efforts, InGaN/ sapphire epitaxial layer dislocations per square centimeter number decreased from 1010 to 108, the industry hopes to drop to 105 or better, at present there is still much room for improvement.

InGaN epitaxial substrates include sapphire, silicon carbide, Zinc Oxide, gallium nitride and aluminum nitride and other types. Its research and development and industrialization are as follows:

1 sapphire epitaxial film: in 2007 the amount of about 5 million (2 inches), is estimated to be used in the amount of in the year of 2010, of which 2/3 is a piece of 2 inches, 1/3 is a piece of 3 inches. By the end of 2007, Showa Showa began to use 4 inch production.

2 silicon carbide epitaxial wafer: the United States CREE company in May 2007 showed a 4 inch zero dislocation single chip. Crystal Institute of Shandong University 3 inches has also been successfully developed, the 2 inch piece has opened the box". Institute of physics, Institute of physics, 2 inch diameter crystal has been developed, dislocation density of less than 100 per square centimeter.

3 Zinc Oxide epitaxial film: generally prepared by hydrothermal method, there are many units such as the Shanghai Institute of Optics and other successful development, but not widely used for InGaN epitaxy.

4: Poland Gan epitaxial Warsaw High Voltage Research Center TOP GaN company in extreme growth conditions (15000 ATM, 1600 C) get with 10mm crystal, 20 slice -30 tablets, the dislocation density of 100 per square centimeter, Gan lasers have been used to make 15 m * 500 m1.89W. The molten salt method used by the Chinese Academy of Sciences has grown into a practical GaN single crystal at a temperature of less than 1000 DEG C and atmospheric pressure. Production of GaN single crystal substrate by HVPE (hydride vapor phase epitaxy) method in Sumitomo chemical industry in April 2003. Nanjing University in the country first with HVPE method to produce 2 inch low error GaN substrate. In April 2007, Japan's Hitachi wire with clearance form stripping method into 3 inch GaN wafer.

5 AlN epitaxial film: Crys-talIS, Washington, USA, was made in May 2006 of 2 inch aluminum nitride substrate.

In addition, Japan Ishida developed a new technology, it will usually MOCVD (metal organic chemical vapor deposition (PPD) deposition and Plasma Physics) phase synthesis, crystal integrity can be improved, eliminating the particles produced by the MOCVD technology, X ray rocking curve of FWHM (FWHM) from 150 arc seconds to 50 seconds of arc, improve the stability of production (between the furnace and furnace and sheet), greatly improving the efficiency of production.

In the field of LED chip manufacturing, technology has also made breakthroughs. Substrate laser stripping technology pioneered by OSRAM, the light efficiency was raised to 75%, is the traditional chip of 3 times, the current domestic units have mastered this technology, and put into production. The improvement of surface roughening or texturing technology can improve the luminous efficiency 30%-50%. Lumileds company developed a flip chip technology, can improve the cooling efficiency, increase the light 1.6 times. The use of indium tin oxide (ITO) materials to achieve a uniform current injection, and improve the efficiency of 60%. Panasonic invented two-dimensional photonic crystals, using light to enhance the 1.7 times -2.7 times. The company used Xuming metal vertical photon crystal structure (MVP), the luminous efficiency reached 90lm/W-100lm/W.

For LED packaging, the requirements of low thermal resistance, good heat dissipation, and reduce junction temperature, improve luminous efficiency; at the same time, the packaging structure to have high light efficiency. The thermal resistance of the device is the sum of the thermal resistance of each structure layer, which should meet the design principle of small number of layers, small thickness, large area and high thermal conductivity of the material.

Steady expansion of semiconductor lighting applications

LED in the display, road traffic lights, mobile phones, landscape lighting, portable lighting and other areas of application has matured. The following is a brief introduction to the development of the 3 main applications in the near future:

1 car lights

Automotive signal lights and interior lighting technology has matured, and will soon be widely used, the next major growth point is the automotive headlamps. In 2007, Audi A86.0 first used LED as a car headlight. Audi R8 uses LED as the high and low beam light. TOYOTA LuxusLS600h uses LED as a low beam headlamp. In the summer of 2008, general Cadillac will also use LED as a high and low beam headlamp. The world's total production of 60 million cars a year indicates that there is still much room for growth in the market.

2.LED LCD backlight

2005, 3.5 inch LCD screen has been fully used LED backlight; by 2006, the use of LED backlight has reached 7 inches screen in; in 2007, the 11 inch screen has also begun to use LED backlight. In the future, 12 inches -15.4 inch notebook LED backlight will have greater growth. Currently, Apple Corp has announced that the company's production of laptops with LED backlight.

Because of the advantages of ultra-thin and power-saving, LED backlight