Improvements in the structural quality of Al_0.48In_0.52As grown by low pressure metal-organic vapour-phase epitaxy

Abstract

High quality Al0.48In0.52As layers with specular morphology and narrowest reported X-ray linewidths of 24 seconds of arc have been grown on InP substrates by LP MOVPE at temperatures of 680-710 degrees C. Background carrier concentrations were in the range 8*1515-4*1016 cm-3 with room temperature mobilities as high as 1900 cm2 V-1 s-1 for growth under optimum conditions. Doping in the range 1017-2*1018 cm-3 was achieved using a H2S/H2 mixture. Improvements in structural and electrical quality were concurrent with successful Schottky barrier measurements where barrier heights of up to phi B=0.73 eV were obtained from C-V measurements on diodes using evaporated PtAu. These results have important implications in the development of Ga0.47In0.53As/Al0.48As HEMTS and InP-based opto-electronic devices.