Experimental study of MISHEMT from 450 K down to 200 K for analog applications

This work presents an experimental analysis of Metal-Insulator-Semiconductor High Electron Mobility transistor (MISHEMT) operating in a temperature range from 450 K down to 200 K, focusing on analog applications. The drain current and consequently the saturation transconductance (gmsat) showed to be slightly dependent on gate length. The output conductance (gD) presents a higher dependence with gate length than gmsat for the whole temperature range due to the influence of MOS conduction that is strongly affected by short channel effect. There is also a kink in the behavior of these parameters at 350 K, most likely due to the competition of temperature effects on different conduction mechanisms. The transistors showed a good performance in terms of analog application, where the intrinsic voltage gain (AV) increases from 38 dB (at 200 K) to 43 dB (at 450 K) for 800 nm gate length while the unity gain frequency (fT) decreases from 1.8 GHz (at 200 K) to 800 MHz (at 450 K) for a gate length of 400 nm, which makes MISHEMT a good candidate for analog applications.