LED substrate, epitaxial and chip technology trends

Technology development and process improvement, so that the cost of LED dropped significantly, and promote the comprehensive development of LED applications. In order to further enhance the energy-saving effect of global LED, the relevant units are to invest a lot of R & D, research deeply on LED performance and reliability, especially on the core technology in the LED substrate, epitaxial, chip, has achieved breakthrough results. This paper puts forward the different technical route and the "ultimate goal" technical scheme for the development of LED, and puts forward some new luminescent materials. To this end, in addition to a brief description of semiconductor lighting upstream industry development situation, development trend also focuses on the LED substrate, epitaxial, chip core technology of dynamic development and discuss the related technology, and technology to reduce the cost of the chip, extension.

Semiconductor lighting upstream industry overview

Semiconductor lighting upstream industry refers to the LED substrate, epitaxial and chip related content, here will briefly introduce the general situation of the upstream industry and the main technical indicators.

1.LED substrate profile

The substrate for the industrialization of LED mainly include sapphire (Al2O3), SiC and Si, CREE, SiC as the substrate, the silicon substrate 8 "Toshiba Co announced on 2013 the growth of LED industry, most of the rest mainly on sapphire. Global production of sapphire substrate has more than and 130, of which there are nearly two years to join the more than and 80. The demand in 2012 of about 96 million (2 to calculate), wherein the patterned sapphire substrate (PSS) accounted for 70%~80%, the 2 "and 4" substrate, because the 52% chip 6 "2" than the same area of the wafer to wafer, so the forecast after a few years will be 6 ". Due to the production capacity is too large, oversupply, resulting in a substantial decline in the price of sapphire chips, about $7~8 per piece. Most of the growth of sapphire crystals using A axial growth, remove the C axis of the wafer, the material utilization is too low, 2 "is about 35%, about 6" is about 20%. The data shows: the CHES method directly on the C axial growth rate can reach 75% by materials, but also reduce the tension and stress, thereby reducing the bending of the substrate wafer warpage and, therefore, greatly improves the production efficiency, the sapphire wafer quality and reduce the cost. In recent years, the world is studying a lot of new substrates for LED, has made great achievements.

China's production of sapphire substrate enterprises about 50, which has been put into operation about 20 or so, some statistics, in 2011 China's production capacity has reached 150 million / year (to be calculated in terms of "), more than the global demand. Moreover, due to the direct production of sapphire PSS substrate is not much, the competitiveness of enterprises is poor, enterprises to transition, integration, merger is inevitable. In addition, there is the growth of the use of Shandong Huaguang SiC substrate LED, Nanchang crystal can use 6 Si substrate growth LED, have achieved good results.

2.LED epitaxy and chip industry overview

LED is engaged in the global extension and chip research and production units of about 160, a total of about MOCVD devices in, the total output of the chip in 2011 was only 82 billion, in 2012 was only in the year of 2012, the excess production rate of up to 35% in. According to the 4 chip calculation, the production capacity of 2 million / month, of which China accounted for 25.8%, Taiwan, Japan, Korea, Korea, 17.3%, the United States of America, 11.8%, Europe, 2.8%, 19.2%. At present, the epitaxial wafer with 2 and 4 based, according to the research institute predicted that in a few years will be based on the chip, more than 50% will be more than 6. Due to the continuous development of epitaxial technology, wafer size continues to expand, coupled with the further improvement of process technology, the cost of epitaxial wafers will be significantly reduced.

LED epitaxial and chip companies in China about more than and 50, which has been put into operation about 36, is preparing to build a total of more than and 20. By the end of 2012 there are about 980 MOCVD devices, most of which are mainly in the "", in 2012 the output of the chip more than 100 billion (including small chips and the $four chip), the output value of up to 6 billion yuan (also reported as $2 million). In addition, China has 16 companies are developing and manufacturing MOCVD equipment, of which there are 8 prototypes have been made, and in the upper reaches of the trial, is expected in 2013 there should be officially put into production of domestic MOCVD equipment. Due to excessive domestic LED upstream enterprises, most of the small size of the enterprise, the lack of R & D capabilities and competitiveness, integration, merger is inevitable.

3.LED main technical indicators

The luminous efficiency as LED mark technology index has greatly improved over the past two years, PHILPS and other large enterprises, Nichia several laboratory level more than 240lm/W Cree, the company announced in February 2013 the laboratory light efficiency reached 276lm/W, TOYOTA announced the implementation of synthetic flux 400lm in LED chip 1mm * 1mm (in large current), Seoul semiconductor light announced the amount of 500lm (in the LED chip 1mm * 1mm and 1000mA current). The level of global LED industry, currently available light effect 120~150lm/W LED products, Cree company announced in early December 2012 to provide the optical efficiency of 186lm/W LED products, the end of December and announced the availability of 200lm/W LED products. Due to the rapid development of LED technology, it can improve the luminous efficiency of LED to what extent is the final result? There are several recent American SSL plan formulation, revision of the level of LED light industry referred to as 266lm/W as the ultimate goal. MITSUBISHI chemical target: 1mm * 1mm chip luminous brightness up to 1000lm luminous flux. Japan made the goal: 2mm * 2mm chip luminous brightness up to 2000~3000lm luminous flux. All of the above mentioned goals can be achieved by single chip LED light source.

Two, LED substrate, epitaxial and chip technology trends

In recent years, the rapid development of LED technology, substrate, epitaxy and chip core technology breakthrough. This chapter will focus on these core technologies