Evaluation of the composition of the interlayer at the inverted interface in InGaP/GaAs heterojunctions

Abstract An evaluation of the composition of the extra interlayer at the GaAs-on-InGaP inverted interface in MOVPE grown In x Ga 1− x P/GaAs heterostructures has been carried out by chemically sensitive (200) dark field TEM in the kinematical approximation. X-ray diffraction measurements have also been performed that showed that the extra interlayer had a negative strain to GaAs. In combination with this result the (200) dark field measurements allowed to establish that the extra interlayer can be either GaAs 1− y P y  ( y =0.55) or In x Ga 1− x As 1− y P y with 0 x 0.069 and 0.55 y 0.707 . P/As intermixing is suggested to be the basic mechanism for the formation of either one of these two alloys. The formation of an interlayer of the quaternary compound additionally requires that In carry-over also occurs.