Substrate orientation dependence of In composition of AlGaInP epilayers grown by MOCVD

Abstract

AlGaInP epilayers of different Al compositions have been grown on (1 0 0) GaAs substrates with a misorientation of 2° and 7° towards (1 1 1)A by metalorganic chemical vapor deposition using tertiarybutylphosphine. High-resolution X-ray diffraction measurements show that the In composition of the AlGaInP epilayer grown on 7° off substrate is lower than that of the AlGaInP epilayer grown on 2° off substrate. Also the difference in the In composition increases with increasing V/III ratio while decreasing with increasing Al composition and substrate temperature. Based on the effect of substrate orientation and temperature on the sticking coefficients and migration lengths of the adatoms, the dependence of In composition on the substrate orientation and growth temperature are discussed.