Growth mode and effect of carrier gas on In0.53Ga0.47As/InP surface morphology grown with trimethylarsine and arsine

Different growth mode have been observed for InGaAs/InP grown with trimethy larsine and arsine by Metalorganic Vapor Phase Epitaxy (MOVPE) when changin g the carrier gas. The surface has been investigated by Atomic Force Micros cope (AFM) for epilayers grown at 600 degrees C under pure hydrogen or a mi xture of hydrogen and nitrogen as carrier gas. The step/terrace surface mor phology was observed for InP/InP and InGaAs/InP (001) using 0.2 degrees off substrates. InP epilayers grown under nitrogen flow show step-bunched terr aces as large as 170 nm. The effect of the group V source for InGaAs/InP ha s been studied. It is shown that the step edge characteristic of step flow growth appears for lattice-matched InGaAs/InP grown with arsine. When using TMAs and hydrogen as a carrier gas, the growth mode and surface roughness depends greatly on V/III ratio and growth temperature. Under nitrogen Row w ith the combination of TMI + TMG + TMAs, pit-like defects (5-8 nm deep) are visible at high surface concentration (10(9)-10(10)/cm(2)). When increasin g V/III ratio, 3D growth occurs simultaneously with pit-like defects, recov ering the whole surface of the sample. Various surface morphology character istics of InGaAs epilayers assessed by AFM characterisation will be present ed and discussed. (C) 1999 Elsevier Science B.V. All rights reserved.