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

Antimonide-based heterostructural p-channel HFET epitaxies consisting of an In
_0.44
Ga
_0.56
Sb quantum well located between AlSb barriers were developed by molecular beam epitaxy. The In
_0.44
Ga
_0.56
Sb 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 cm
²
/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.