Threshold and sheet concentration sensitivity of high electron mobility transistors

We present results of an analysis of the dependence of the threshold voltage and the sheet carrier concentration on background substrate doping, Al1 - xGaxAs doping, thickness, and metal barrier height in the high electron mobility transistor (HEMT) at room and liquid nitrogen temperatures. The sensitivity of threshold voltage and sheet carrier concentration to buffer layer or substrate background concentrations improves at lower temperatures. The sensitivity of threshold voltage and sheet carrier concentration to Ga1 - xAlxAs doping and thickness degrades at lower temperatures. The threshold sensitivity to barrier height is temperature independent but increases for sheet carrier concentration at lower temperatures. The design of a device structure for integrated circuit application with minimial threshold variations will require an optimal design of the device and will depend on the status of control of the various parameters.