Preparation of GaN-On-Si based thin-film flip-chip LEDs
Silicon substrate is considered the best altemative substrate for GaN growth and low cost LED manufacturing.The difficulty of GaN growth on silicon is caused by the 17% lattice constant mismatch and the 59% thermal expansion coefficient mismatch.The thermal expansion mismatch between GaN and silicon leads to tensile stress in GaN and often cracks in the GaN epitaxial film.By optimizing the buffer layer,we are able to grow crack-free GaN on silicon with a similar quality to that of GaN grown on sapphire or SiC substrate.Based on this new GaN EPI breakthrough,an all new technology platform has been developed to manufacture high performance lighting class LEDs.This new technology can significantly reduce the cost of LED while improving the performance.The typical performance from a 45mil silicon substrate LED is about 120lm/W in cool white at 350mA,which is similar to the product performance from the tier one companies using traditional sapphire based substrate.More ever,we found that chips made from silicon substrate have a lower reverse leakage and better resistance to ESD.More than 5000hrs accelerated reliability test showed that these chips are as reliable as sapphire based chips.In this paper,GaN based MQW LED EPI layers were grown on Si(111) substrate by MOCVD using AIN as the buffer layer.High light extraction LEDs were made by substrate transfer technology which combines thin-film and flip-chip design.Performance characteristics of blue and white 1.1 × 1.1mm2 LED lamps are described.The optical powers and external quantum efficiency for a silicone encapsulated blue lamp are 546mW and 50.3% at forward current of 350mA,while the photometric light output for a white lamp packaged with standard YAG phosphor is 120.1 lm.
silicon substrate GaN flip chip LED
Shaohua Zhang Bo Feng Qian Sun Hanmin Zhao Min Wang
Lattice Power(Jiangxi)corporation., 699 North Aixi Lake Road, Nanchang, Jiangxi Province P.R.China, 330029
国际会议
9th China International Forum on Solid State Lighting(第九届中国国际半导体照明论坛)
广州
英文
44-44
2012-11-05（万方平台首次上网日期，不代表论文的发表时间）