Interdiffusion in mercury cadmium telluride evaluated from vapor phase growth kinetics

Abstract

A method is presented for determining interdiffusion coefficients from the kinetics of isothermal vapor phase epitaxial growth of mercury cadmium telluride (Hgl -,Cd,Te). After an initial transient, growth is interdiffusion limited. Interdiffusion coefficients in the composition range 2 = 0.1 to 0.7 and a temperature range of 450 to 700 "C are determined using a simple geometric analysis of the composition profiles obtained in this interdiffusion limited regime. The technique offers advantages in simplicity and added control over the defect nature of the material during the interdiffusion process. The interdiffusion coefficients for the composition and temperature range studied are represented by the following equation: D,(cm2/s) = 300 exp (-7.532) exp (-1.92 eV/kT). Comparison with other studies shows good agreement. E s wird eine Methode zur Bestimmung der Interdiffusionskoeffizienten aus der Kinetik des isothermen gasphasen-epitaktischen Wachstums von Quecksilber-Kadmiumtellurid (Hgl -&d,Te) angegeben. Nach einer Anlaufphase ist das Wachstum diffusionslimitiert. Diffusionskoeffizienten im Zusammensetzungsbereich z = 0,l bis 0,7 und einem Temperaturbereich von 450 bis 700 "C werden mittels einfacher geometrischer Analyse der in diesem interdiffusionsbegrenzten Regime erhaltenen Verbindungsprofile bestimmt. Die Technik besticht durch ihre Einfachheit und um-faSt zugleich eine Kontrolle iiber die Defektart des Materials wiihrend des Interdiffusionsprozesses. Die Interdiffusionskoeffizienten im untersuchten Zusammensetzungs-und Temperaturbereich lassen sich durch die Gleichung D,(cm2/s) = 300 exp( -7,532) exp (-1,92 eV/kT) darstellen. Ein Vergleich mit anderen Untersuchungen zeigt gute Ubereinstimmung. Stanford, CA 94305, USA.

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

“…It has been found, in agreement with Stevenson et al [28,29], that the film thickness and surface chemical composition are independent of the crystalline orientation (Table 3). 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].…”

“…5a) and (1 1 1)Te (Fig. 5b) [28,29]. The observed differences probably can be attributed to the initial growth stages where kinetic control could be determined by the surface phenomena, in which crystal structure and surface order have an important role for each crystallographic orientation.…”

Defect Distribution and Properties of (211) ISOVPE-MCT Films

“…The interdiffusion coefficients differ at most by an order of magnitude and they were comparable with values obtained by the authors of this work and by other researchers that employed different growth conditions [6,7].…”

Simulation of HgTe/CdTe interdiffusion using fundamental point defect mechanisms

“…All of the characterization techniques except DCD determine composition as a function of depth. 12,17 Figure 1 shows the reported interdiffusion rates under Hg saturated conditions for x Cd = 0. [7][8][9][10] Although several researchers show "raw" Hg and Cd profiles as a function of depth, most report D MCT .…”