柱状与孔状图形衬底对MOVPE生长GaN体材料及LED器件的影响  

Influence of pillar-and hole-patterned sapphire substrates on MOVPE grown GaN bulk and LED structures

作　　者：江洋[1] 罗毅[1] 汪莱[1] 李洪涛[1] 席光义[1] 赵维[1] 韩彦军[1] 

机构地区：[1]清华大学电子工程系 集成光电子学国家重点实验室,北京100084

出　　处：《物理学报》2009年第5期3468-3473,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60536020,60723002);国家重点基础研究发展计划“973”(批准号:2006CB302801,2006CB302804,2006CB302806,2006CB921106);国家高技术研究发展计划“863”(批准号:2006AA03A105);北京市科委重大计划(批准号:D0404003040321)资助的课题~~

摘　　要：在柱状图形蓝宝石衬底(PSS-p)和孔状图形蓝宝石衬底(PSS-h)上外延了GaN体材料和LED结构并进行了详细对比和分析.X射线衍射仪(XRD)和原子力显微镜(AFM)测试结果表明,PSS-h上体材料的晶体质量和表面形貌都优于PSS-p上体材料的特性,通过断面扫面电子显微镜(SEM)照片看出PSS-h上GaN的侧向生长是导致这种差异的原因.另外,基于PSS-p和PSS-h上外延的LED材料制作而成的器件结果表明,其20mA下光功率水平相比普通蓝宝石衬底(CSS)分别提高了46%和33%.通过变温光荧光谱(PL)分析发现,样品的内量子效率十分接近.因此,可以推断PSS-h上侧向外延中存留的空气隙则会影响光提取效率的提高.Bulk GaN material and LED structures on pillar-patterned sapphire substrates （PSS-p） and hole-patterned sapphire substrates （PSS-h） were grown by MOCVD and the characteristic was compared in detail. X-ray diffraction and atomic force microscope measurements show a better crystal quality and surface morphology of GaN on PSS-h than that of GaN on PSS-p, which is due to the lateral growth of GaN on PSS-h observed from cross-sectional scanning electron microscopy. Furthermore, the output power of LED on PSS-p and PSS-h with 20 mA injection current are 46% and 33% higher than LED on conventional sapphire substrate, respectively. The temperature-dependent photoluminesence measurements indicate that the internal quantum efficiencies of all samples are quite close. Therefore, the airgaps between GaN and PSS-h act against the improvement of light extraction efficiency.

关 键 词：蓝宝石图形衬底 氮化镓 发光二极管 侧向生长 

分 类 号：O471[理学—半导体物理]