从电极偏置环境、二维异质结能带及沟道电子状态的研究出发,发现了沟道中存在具有不同输运特性的高能正常电子和低能慢电子,建立起新的慢电子电流崩塌模型。在器件射频工作中通过正常输运电子到慢电子的转换过程解释了射频电流崩塌行为。沟道中的慢电子是产生射频电流崩塌的真正缘由。运用这一慢电子电流崩塌模型解释了目前用耗尽模型不能解释的大量实验结果。最后提出了通过异质结构优化设计来消除慢电子,解决电流崩塌难题的新途径。
From the investigation of HFET electrode bias environment,two dimensional heterostructure bands and electron states,it is found that there are two sorts of electrons in the channel: the normally transport electrons with high energy and slow transport electrons with low energy,from which a novel radio frequency current collapse model is established.In the radio frequency operation of GaN HFET,the current collapse is explained by the transformation between these two sorts of electrons.It is the slow transport electrons in channel that induce the current collapse.By using this slow transport electron current collapse model,a lot of new current collapse experimental behaviors have been explained.At last,a new path to eliminate current collapse in GaN HFETs through optimization of heterostructure design to reduce the slow transport electrons is proposed.