Microwave performance of a digital alloy barrier Al(Sb,As)/AlSb/InAs heterostructure field-effect transistor

High-speed, digital alloy barrier-based, Al(Sb,As)/AlSb/InAs heterostructure field-effect transistors (HFETs) fabricated using a standard mesa process are demonstrated. Current gain cutoff frequencies f/sub T/ of 38.5 GHz were extracted from the measured scattering parameters for devices with a 0.6- mu m gate length and a 3- mu m source-to-drain separation. A significant output conductance depressed f/sub max/ to 40 GHz. The results show the feasibility and potential of InAs/AlSb-based HFETs for high-speed electronics applications. >