Effects of physical parameters on subthreshold characteristics of nitride and antimonide-based double material gate (DMG) HEMTs

Abstract

In this papar we have varied the physical parameters of double material gate (DMG) HEMT and noted the change in subthreshold characteristics. The physical parameters are: control-gate length, barrier layer thickness and the work function difference between two gate materials. A semi-classical analytical model has been used to determine the channel potential and electric field. One nitride-based and three antimonide-based formations have been used in this work and their results have been compared. We have found that nitride-based DMG HEMTs are less sensitive to process variation of gate fabrication compared to antimonide-based DMG HEMTs. It has been seen that variation in barrier layer thickness affects nitride-based HEMTs more strongly than antimonide-based DMG HEMTs, while the effect of change in workfunction difference is more prominent in antimonide-based HEMTs. Among the antimonide-based HEMTs, it have been seen that the formation with deep conduction band discontinuity is more susceptible to change in control-gate length than formations with shallow conduction band discontinuity. But effects of barrier layer thickness change and change in workfunction difference are more noticeable in shallow conduction band formations, making these formations more effective as double material gate (DMG) structures.