The growth and characterization of uniform Ga1-xInxAs (X ≤.25) by Organometallic VPE

Abstract

Compositionally uniform Ga1-xInxAs epitaxial layers with 0 ≤ x ≤ 0.2 5 have been grown by organometallic VPE on ◃100▹ GaAs substrates. Compositional uniformities of ±0.25 InAs percentage and ±5% thickness over a 3-cm long wafer have been achieved and are essentially independent of small changes in reactor geometry such as the angle of the susceptor tilt or wafer position on the susceptor. Growth has also been demonstrated at x = 0.52. The Ga1-xInxAs is grown using trimethylgallium (TMGa), triethylindium (TEIn) or trimethylindium (TMIn), and trimethylarsenic (TMAs). The use of TMAs eliminates the roomtemperature gas-phase reaction between AsH3 and either TEIn or TMIn, and allows one atmospnere pressure growth conditions to be used without any special mixing arrangements in the reactor. The comparative effects of using TEIn or TMIn as the In source are discussed in terms of crystal quality. Data on crystal composition as a function of gas phase composition and growth rate as a function of composition are presented, and n doping and carrier mobilities and p doping of Ga.80In.20As ars characterized. The vapor pressure of TMIn at 0°C is determined to be 0.21 mmHg.