X-ray CTR scattering measurement of InP/InGaAs/InP interface structures fabricated by different growth processes

Hetero-interfaces of InP/InGaAs (three monolayers (ML))/InP samples grown b y organometallic vapor phase epitaxy (OMVPE) were investigated using X-ray crystal truncation rod (CTR) measurement. The samples were prepared with th ree different source-gas flow-sequences: (a) conventional sequence, (b) gro wth interruption, and (c) Ga and In source-gas pulse injection. The results of the X-ray CTR measurement showed that the interfaces between InP cap an d InGaAs layers of (b) and (c) were sharper than that of (a) as intended. H owever, the amount of As in (b) was less than that designed since As atoms desorbed even from the InGaAs layer during the growth interruption. Surpris ingly, the Ga atoms distributed wider and peal; compositions of Ga were sma ller than those designed for all the samples. It means that the quantum wel l structures are far from those designed and expected. It suggests that mor e efforts are necessary to control the distribution of group-m atoms after we solved the problem of group-V atom distributions. (C) 2000 Elsevier Scie nce B.V. All rights reserved.