穿透型V形坑对GaN基p-i-n结构紫外探测器反向漏电的影响  

Influence of penetrating V-pits on leakage current of GaN based p-i-n UV detector

作　　者：张爽[1] 赵德刚[1] 刘宗顺[1] 朱建军[1] 张书明[1] 王玉田[1] 段俐宏[1] 刘文宝[1] 江德生[1] 杨辉[1] 

机构地区：[1]中国科学院半导体研究所集成光电子国家重点联合实验室,北京100083

出　　处：《物理学报》2009年第11期7952-7957,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60776047;60506001;60476021;60576003;60836003)资助的课题~~

摘　　要：研究了GaN基p-i-n(p-AlGaN/i-GaN/n-GaN)结构紫外探测器的漏电机理.实验发现,在位错密度几乎相同的情况下,基于表面有较高密度的V形坑缺陷材料制备的器件表现出较高的反向漏电.进一步的SEM测试发现,这种V形坑穿透到有源区i-GaN、甚至n-GaN层.在制备p-AlGaN电极时,许多金属会落在V形坑中,从而与i-GaN形成了肖特基接触,有些甚至直接和n-GaN形成欧姆接触.正是由于并联的肖特基接触和欧姆接触的存在导致了漏电的增加.The leakage mechanism of GaN-based p-i-n （p-AlGaN/i-GaN/n-GaN） UV detector has been investigated. With the same dislocation density, devices made from material with higher density of V-pits on surface produce larger leakage current. SEM images show that some V-pits penetrate into i-GaN layer, sometimes even the n-GaN layer. If p-ohmic contact metal （Ni/Au） deposits in the V-pits, Schottky contact would be formed at the interface of metal and i-GaN, or form ohmic contact at the interface of metal and n-GaN. The existence of parallel Schottky junction and ohmic contact resistance enhances the leakage current greatly.

关 键 词：GAN 紫外探测器 V形坑 反向漏电 

分 类 号：TN23[电子电信—物理电子学] TP334.22[自动化与计算机技术—计算机系统结构]