Materials growth for InAs high electron mobility transistors and circuits

Abstract

High electron mobility transistors (HEMTs) with InAs channels and antimonide barriers were grown by molecular beam epitaxy. Both Si and Te were successfully employed as n-type dopants. Sheet resistances of 90–150 Ω/□ were routinely achieved on a variety of heterostructures with nonuniformities as low as 1.5% across a 75 mm wafer. X-ray diffraction measurements show that the InAs channels are in tension, coherently strained to the Al(Ga)Sb buffer layers. Atomic force microscopy measurements demonstrate that the surfaces are relatively smooth, with rms roughness of 8–26 Å over a 5×5 μm2 area. These results demonstrate that the growth of InAs HEMTs has progressed to the point that the fabrication of circuits should be feasible.