Low-temperature characteristics of In0.7Ga0.3As PHEMTs

In this paper, we report on temperature dependent DC characteristics of In
_0.7
Ga
_0.3
As Pseudomorphic-HEMTs (PHEMTs) on InP substrate. First, we have fabricated the In
_0.7
Ga
_0.3
As PHEMTs with various values of L
_g
, ranging from 10 μm to 2.5 μm. The fabricated device with L
_g
= 2.5 μm exhibits excellent subthreshold-swing (SS) of 64 mV/decade at room temperature. Note that this is close to 60 mV/decade, which is a theoretical limit at room temperature in a FET configuration. Next, we have measured current-voltage characteristics at various values of temperatures, from 300 K to 80 K. Finally, we have investigated the temperature-dependent DC characteristics of the In
_0.7
Ga
_0.3
As PHEMTs, in terms of output, subthreshold, and transconductance characteristics.