Improved Charge Control Performance in InAs/AlSb-Based Heterostructure Field-Effect Transistors

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