Atomic layer epitaxy of AlxGa1−xAs and device quality GaAs

Abstract Recent progress of III–V compounds grown by ALE was mainly focused on binary alloys with very little activity on ternary alloys. This has limited the usefulness of ALE in the growth of heterojunction device structures. We report the ALE growth of Al x Ga 1− x As (0 x 3 exposure. Atomic layer epitaxy was carried over a temperature range from 550 to 700°C, and monolayer growth was only observed over a fairly narrow range of column III flux. Al incorporates during ALE film growth more efficiently than during MOCVD growth in the same reactor. The ALE films show better composition uniformity than the MOCVD ones. AlGaAs/GaAs quantum wells were also grown solely by ALE at the same temperature with very uniform well thickness. High quality ALE grown GaAs was also achieved. Background carrier concentration in 10 14 -10 15 cm -3 range was obtained with 77 K mobility about 30,000 cm 2 /V·s for 2 μm thick films. The 4 K photoluminescence displayed well resolved bound excitonic transitions characteristics of high purity GaAs. The material quality improved with increasing V/III ratio and growth temperature.