DIFFUSION AND ELECTRICAL-ACTIVITY OF INDIUM IN (HG,CD)TE

Authors
Citation
G. Weck et K. Wandel, DIFFUSION AND ELECTRICAL-ACTIVITY OF INDIUM IN (HG,CD)TE, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 12(6), 1994, pp. 3023-3032
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
ISSN journal
0734-2101
Volume
12
Issue
6
Year of publication
1994
Pages
3023 - 3032
Database
ISI
SICI code
0734-2101(1994)12:6<3023:DAEOII>2.0.ZU;2-7
Abstract
Indium diffusion into Hg1-xCdxTe (0.2<x<0.3) was carried out in a two zone furnace in the diffusion temperature range from 240-380 degrees C . The second zone temperature was chosen to maintain a constant concen tration of mercury vacancies if no indium is present. Typical indium p rofiles consist of an erfc-like segment at higher concentration and an abrupt profile at lower concentration at the diffusion front. The dep th of the latter coincides very well with the depth of the n-type regi on. An electron concentration up to 5X10(18) cm(-3) was observed. The electrical activation decreases with higher indium concentration as wa s elucidated by differential Hall measurements. The chemical indium pr ofiles are interpreted in terms of an interstitial diffusion together with two incorporation mechanisms of different net charge transfer: th e Frank-Turnbull and the kick-out mechanisms. A numerical diffusion mo del is outlined based on the assumption of a local equilibrium for sit e occupation and a linear response of the change of the defect concent ration to the deviation from equilibrium. Although the profiles depend strongly on the indium surface concentration, an In-concentration ind ependent diffusion coefficient of interstitial indium D-In,D-i=(5.4/9. 2) X10(-5) cm(2) s(-1) exp[(-922+/-20 meV)/k(B)T] fits the experiments . Large variations of the indium surface concentration are apparently caused by storage in air between wet chemical preparation and enclosur e of the specimen in the ampoule.