Device behaviour and zero temperature coefficients analysis for microwave GaAs HEMT

Detailed analysis of device behaviour on the zero-temperature coefficient (ZTC) points for microwave GaAs based high-electron mobility transistor is presented by means of on-wafer measurements over the temperatures between −40 and 150 °C. This zero temperature coefficient points found not only in the transfer and transconductance curve but also in intrinsic transconductance gmo, output conductance gds, small signal gain S21, and minimum noise figure NFmin also exhibits ZTC. It is found that the zero temperature coefficients points are impacted by both threshold voltage and drain bias. The transfer current base, ZTCIds moved from 0.1 V to −0.2 V of Vgs trace and transconductance based, ZTCgm moved from −0.3 V to −0.6 V of Vgs trace with the drain bias, Vds varies from 1 V to 5 V. The behaviour of some intrinsic equivalent circuit parameters along with cut-off frequency, ft at both ZTC bias points opens some crucial insight and opportunities in microwave device design for low and high temperature applications.