As a result , the fermi level at the surface will shift towards the valence band maximum ( vbm ) . accordingly the band bending increases , and the surface depletion layer thickness enhances , therefore , the channel thickness reduces . this is the main factor resulting in the decrease of saturated drain - source current 表面费米能级向价带顶移动,能带弯曲加剧,肖特基势垒高度增加,表面耗尽层变厚,导电沟道变窄,是导致源漏饱和电流下降的主要因素。
In this paper , the theory of negatively charged surface states is used to investigate dynamic breakdown characteristics and the increase of gate - drain breakdown voltage as well as the reduction of saturated drain - source current after sulfur passivation . the measure which can improve the stability of sulfur passivation is proposed 本论文通过对gaasmesfet击穿机理和硫钝化机理的研究,用负电荷表面态理论,解释了gaasmesfet动态击穿特性及硫钝化后栅漏击穿电压增大、源漏饱和电流减小的机理,提出了改善硫钝化稳定性的措施。