钝化与场板结构对AlGaN/GaN HEMT电流崩塌的影响  

Effects of Passivation and FP Structure on Current Collapse in an AlGaN/GaN HEMT

作　　者：马香柏[1] 张进城[1] 郭亮良[1] 冯倩[1] 郝跃[1] 

机构地区：[1]西安电子科技大学微电子学院宽禁带半导体材料与器件教育部重点实验室,西安710071

出　　处：《Journal of Semiconductors》2007年第1期73-77,共5页半导体学报（英文版）

基　　金：国家重大基础研究发展计划(批准号:2002CB3119;513270407);国防科技重点实验室基金(批准号:51432030204DZ0101;51433040105DZ0102)资助项目~~

摘　　要：由于AlGaN/GaNHEMT的几何结构以及很强的极化效应,柵漏区域的电场很大,以至于电子可以从柵隧穿到AlGaN表面.隧穿的电子在表面累积,导致柵下耗尽区的电子向漏端延伸,从而引起漏极电流的下降.文中采用应力测试方法,研究了未钝化、钝化以及场板三种结构的AlGaN/GaNHEMT的电流崩塌程度.实验结果表明,钝化隔断了电子从柵隧穿到AlGaN表面的通道,场板结构能够有效降低柵边缘电场,均减少了电子从柵隧穿到表面陷阱的几率,从而使虚柵的作用减弱,有效地抑制了电流崩塌效应.Due to the geometry and polarization of AIGaN/GaN HEMTs, the electric field in the gate-drain region is very high, and is sufficient to produce a tunneling current from the gate metal to the surface of the AIGaN barrier layer. The electrons that tunnel to the semiconductor surface can accumulate on the surface near the gate, resulting in the extension of the depletion region and current collapse. Bias stress measurements were made to determine an AIGaN/GaN HEMT＇s current collapse. Surface passivation prevents the electrons from getting trapped at the surface, and a field plate suppresses the electric field at the gate edge, thereby reducing the gate leakage by a significant factor. Thus the current collapse can be effectively suppressed by surface passivation and the field-plate structure.

关 键 词：电流崩塌 钝化 场板结构 

分 类 号：TN322.8[电子电信—物理电子学]