高效大功率LED用蓝宝石图形衬底的制备

Preparation of Patterned Sapphire Substrate for High-efficiency and High-power Light Emitting Diodes

首先在蓝宝石衬底上旋涂PMMA/copolymer双层胶,然后再进行电子束光刻处理,随后溅射铝膜,并结合剥离技术,从而制备图形化金属铝膜;最后再采用两步热处理法,使图形铝膜发生固相外延反应。在此过程中,侧重于电子束光刻和高温热处理的工艺优化研究。SEM测试结果表明,图形化铝膜在450℃低温氧化热处理24 h后,其图形形貌没有发生明显改变;在温度低于1200℃的高温热处理1 h后,图形仍然存在。HRXRD分析表明,图形化铝膜在450℃低温热处理24 h后再在1000℃高温热处理1 h,可在蓝宝石衬底上形成氧化铝外延薄膜;并且相比于基片,氧化铝外延薄膜的结晶质量还有所提高。本方法成功实现了高效大功率用LED蓝宝石图形衬底的制备。

In this paper, patterned sapphire substrates were prepared by dual stage annealing of patterned AI films prepared by electron beam lithography of PMMA/copolymer bilayer resist. The designed four kinds of A1 patterns were obtained by optimizing the e-beam lithography process. The little change in the morphology of the patterns was observed after annealing for 24 h at 450 ℃. The patterns were retained after high temperature annealing for 1 h at less than 1200 ℃ HRXRD results indicated that the island patterns are epitaxially grown on sapphire substrates by dual-stage annealing for 24 h at 450℃ and then 1 h at 1000 ℃. Furthermore, the alumina epitaxial patterns have higher crystalline quality compared with sapphire substrates. The above-mentioned method has sueessfully achieved the preparation of patterned sapphire substrates for high-efficieney ＆ high-power LED applications.