Thermodynamics of Impurity Doping Reactions in Vapor Growth of Ge

Abstract

The incorporation of impurities into single crystal layers of Ge grown by the disproportionation reaction 2GeI2\\rightleftarrowsGe+GeI4, is studied thermodynamically. Impurity iodides formed in the source region are carried over substrate wafers where impurity atoms are liberated mainly through the reduction by Ge or GeI2. The amount of impurity incorporated depends largely upon the yields of reactions involved in the doping process, and the analysis leads to the conclusion that Sb, P and As are favorable as donor impurities while Ga, In and BI3 as acceptor impurities.