Improved charge control and frequency performance in InAs/AlSb-based heterostructure field-effect transistors

We demonstrate high-speed InAs/AlSb-based heterostructure field-effect transistors (HFET's) displaying greatly improved charge control properties and enhanced high-frequency gate performance. Microwave devices with a 0.5×84 μm
²
exhibit a peak unity current gain cut-off frequency of f
_T
=93 GHz. The HFET usable operational range was extended to V/sub DS/=1.5 V (from V/sub DS/=0.4-0.5 V) thus greatly enhancing the applicability of InAs/AlSb-based HFET's for low-power, high-frequency amplification. We also report on the bias dependence of f
_T
, and demonstrate that InAs/AlSb-based HFET's offer an attractive frequency performance over an adequately wide range of drain biases.