Substrate orientation effect on Zn δ-doping in GaAs grown by metal organic vapour-phase epitaxy

Abstract

The substrate orientation dependence of Zn incorporation on the nongrowing surface in the AsH3 containing ambient was investigated using Zn δ-doped layers in GaAs grown by metal organic vapour-phase epitaxy (MOVPE). We found that the Zn δ-doping concentration significantly decreases with an increase of the (1 0 0) off-angle towards (1 1 1)B along the [0 1 1] direction. The Zn incorporation on the nongrowing As-terminated (1 1 1)B surface is negligible. A notable increase of the Zn incorporation was observed with increasing the (1 0 0) off-angle towards (1 1 1)A, while the maximum Zn δ-doping concentration was obtained on the (3 1 1)A surface. The Zn density decreases with a further increase in the (1 0 0) off-angle towards (1 1 1)A after (3 1 1)A. Based on the bonding configurations of the nongrowing surface, the possible mechanism of orientation effect on Zn incorporation is discussed. © 1998 Elsevier Science B.V. All rights reserved.