中文摘要：

设计了一种实验方法用以研究AlGaN／GaN外延表面陷阱充电效应对于薄膜电阻的影响，该效应与GaN基HEMT电流崩塌现象直接相关。测量获得了AlGaN／GaN异质结结构薄膜电阻在周期栅脉冲信号下的变化规律。薄膜电阻在低频区域对脉冲频率十分敏感，而在高频时出现饱和。当信号频率足够高时（≥4kHz），AlGaN／GaN簿膜将呈现高阻，器件关断，说明二维电子气已被表面陷阱电荷耗尽。该实验为研究表面陷阱与电流崩塌效应的关系提供了新的证据。

英文摘要：

An experiment was designed to investigate the effects of the surface trapping process on the sheet resistance of the AlGaN/GaN film. The variation of the sheet resistance was measured while periodical square signals were applied on a specially designed AIGaN/GaN HEMT. It is demonstrated that the sheet resistance depends on the signal frequency. While the frequency applied is higher than 4KHz, the sheet resistance becomes very large and the device is cut off. It directly evident that the 2DEG at the AlGaN/GaN interface is depleted by the surface trapped charges. The experiment can be assisted in the further investigation of the role of surface traps in current collapse effect.