Growth Kinetics of Hg_1-xCd_xTe Epilayers by Semiclosed Open-Tube Isothermal Vapor Phase Epitaxy

Abstract

Hg1-x Cd x Te (MCT) epilayers were grown on (110) CdTe substrates by semiclosed open-tube isothermal vapor phase epitaxy (ISOVPE). The effects of growth parameters on the surface compositions (x) and thicknesses of the epilayers have been clarified and discussed using the general ISOVPE model. It is found that the growth is limited by the interdiffusion process. The growth kinetics in the interdiffusion control regime was also studied. The growth rate followed the t 1/2 dependence expected for interdiffusion-limited processes, and the growth rate constant (A) is given by the Arrhenius form with A 0=6.63×10-2 cm2/s and the activation energy Q=1.33 eV. The interdiffusion coefficients for the composition (0.05<x<0.5) and temperature (698 K≤T≤ 773 K) are expressed as D(cm2/s)=550exp (-9.27 x)exp (-1.95 eV/κT) by Fleming-Stevenson analysis.

ISOVPE MCT films grown on pure and alloyed CdTe substrates with different crystalline orientations

“…These facts were experimentally supported by the linear relation between film thickness and the square root of time showing a diffusive-controlled process [30][31][32][33][34][35][36]. Besides, this experimental evidence can be explained by the Djuric model over the wide temperature and pressure range used in the ISOVPE MCT growth, which is indicative of a diffusion-limited process [37].…”