High optical efficiency Ga N based blue LED on silicon substrate
JIANG Feng Yi;LIU Jun Lin;WANG Li;XIONG Chuan Bing;FANG Wen Qing;MO Chun Lan;TANG Ying Wen;WANG Guang Xu;XU Long Quan;DING Jie;WANG Xiao Lan;QUAN Zhi Jue;ZHANG Jian Li;ZHANG Meng;PAN Shuan;ZHENG Chang Da;National Engineering Technology Research Center for LED on Si Substrate,Nanchang University;
After nearly ten years of exploration, our team firstly had a breakthrough in the technologies of materials growth and thin film chip manufacturing for high efficiency Ga N based blue LED on silicon substrate in the world. The internal quantum efficiency and extraction efficiency of the vertical structure blue LED chips reached 80%. These LED chips have been realized mass production, and been successfully used in street lamps, miner's lamp, down light, bulb light, flashlight and display imaging etc. In this paper, the related key technologies are comprehensive and systematically introduced. Selective-Area-Growth and Maskless-Micro-Epitaxial-Lateral-Overgrowth technologies were invented, by which a high crystalline quality Ga N film was achieved with an only 100 nm Al N buffer layer. A set of systemic technologies were invented for manufacturing vertical thin film structure LED on silicon substrate, included high reflectance low resistance P type ohmic contact electrode, high stability low resistance N type electrode ohmic contact, surface roughening, complementary electrode, releasing residual tensile stress of Ga N film technologies etc. At 350 m A(35 A/cm2), the light output power of blue LED(450 nm) on silicon is 657 m W, and external quantum efficiency of it is 68.1%.