Epitaxial Vapor Growth of Ge Single Crystals in a Closed-Cycle Process

Abstract

The Ge-I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> disproportionation reaction in a sealed tube will deposit Ge epitaxially upon Ge seeds at a typical rate of 10µ/hr at a typical temperature of 400°C. Dislocations are of the same kind and approximate concentrations as observed in ordinary melt-grown Ge. Chemical purity is comparable to the best melt-grown Ge. The fraction of donors transferred from the source material to the deposited material is nearly unity over a wide range of concentrations, while the fraction of acceptors transferred is considerably less than unity. However, either n-type or p-type Ge can be deposited, and by using two sources within the same tube alternating layers can be obtained.