Growth of InAs by MOVPE using TBAs and TMIn

Abstract

The growth of bulk heteroepitaxial layers of InAs on GaAs substrates by atmospheric pressure MOVPE is described. Tertiarybutylarsine [TBAs] and trimethylindium [TMIn] were used as the precursors. We present a study of the variation of morphology and electrical quality of the layers whilst varying the V/III ratio and growth temperature. The morphology of the layers varied between a lumpy surface consisting of elemental indium [excess group III] through smooth specular layers to dendritic growth [excess group V]. The morphology was also affected by the temperature, with an excess indium surface below 460° C and varying through specular surfaces between 480 - 540° C and bumpy irregular surfaces above 550° C. The electrical quality of the layers was poor when the morphology was poor, but showed a peak in mobility at 480° C and a V/III ratio of 0.83:1. The maximum mobility at 77 K was >32,000 cm²/Vs with a carrier concentration of 7.1 × 10¹⁵ cm^-3.