Ti- and Pt-based Schottky gates for InGaSb p-channel HFET development

Abstract

Antimonide-based heterostructural p-channel HFET epitaxies consisting of an In0.44Ga0.56Sb quantum well located between AlSb barriers were developed by molecular beam epitaxy. The In0.44Ga0.56Sb channel layer was compressively strained to enhance hole mobility. Room-temperature Hall measurements to the as-grown materials exhibited a hole mobility as high as 895 cm2/V s. Ti/Pt/Au and Pt/Ti/Pt/Au metals were utilized in Schottky gate metallization processes for evaluating their effects on the device performance. Considering the diffusivity of Pt metals, the devices with as-deposited and annealed Pt-based gates were characterized simultaneously and compared with the ones with Ti-based gates. The devices with Ti-based gates yielded superior dc and rf performances to those with Pt-based gates.