栅脉冲下AlGaN/GaN HEMT电流崩塌效应研究

Investigation of Gate Pulsed Producing Current Collapse in AlGaN/GaN HEMTs

源于AlGaN/GaNHEMT器件的大量测试分析发现,栅脉冲条件下漏极电流比直流情况下减小了47%;随着信号频率的改变,漏极电流按μnCoxW[α+(0.13+0.64f)VGS+(0.13+0.32f)VGS2](VGS-Vth)2/L的规律变化;脉冲信号宽度对漏电流崩塌影响较小.基于实验结果的理论分析认为,电子从栅极注入到栅漏之间并被表面态所俘获,在沟道中形成增加的耗尽层,使得沟道二维电子气浓度减小,从而导致形成电流崩塌效应的主要原因之一.该结论有助于AlGaNHEMT器件脉冲条件下电流崩塌效应理论解释和器件应用.

Measurements originated from A1GaN/GaN HEMTs show that current reduces about 47% in gate pulsed condition, and with pulse frequency exchanged gate pulsed current equals to μnCur[α＋（0. 13＋0. 64f）VGS ＋ （0. 13＋0. 32 f）VGS^2]（VGS-Vth）^2/L. Pulse width influences less on current collapse. The analysis based on experimental findings indicates that since gate injected electron, which is trapped by surface states between drain and gate, forms an extended depletion layer in channel The 2 dimensional electron gas density is reduced and a main current collapse producing reason is generated. The conclusion can assist AlGaN/GaN HEMT＇s theoretical explanation of current collapse and it device in application under pulsed condition.