Molecular beam epitaxial growth and characterization of InAs layers on GaAs (001) substrate

Abstract

High-quality InAs epilayers were grown onto GaAs (001) substrate by molecular beam epitaxy. The optimal growth conditions were examined over a wide range of substrate temperature, substrate offcut orientation, and As4/In flux ratio. The surface morphology, electrical and structural properties were investigated by Nomarski optical microscopy, Hall effect measurement, and X-ray diffraction, respectively. It is worth noting that InAs layers grown on GaAs (001) substrate with 2° offcut towards 〈110〉 have better crystalline quality and electrical properties than that grown on GaAs substrate without offcut. The results indicated that the layers grown at 400 °C, with a group V/III flux ratio of 8.5, yielded to the highest electrical quality, with a Hall mobility of 22,420 cm2/Vs at 80 K and 12,970 cm2/Vs at room temperature. It is found that the top part of 5 µm-thick InAs layer exhibits a high Hall mobility of 77,380 and 25,275 cm2/Vs, at 80 and 300 K, respectively.