NATIVE DEFECTS IN THE ALXGA1-XSB ALLOY SEMICONDUCTOR

Defect concentrations in Al(x)Ga(1-x)Sb which is in equilibrium with a liquid phase are calculated. When the liquid phase is Ga rich, a Ga antisite (Ga(Sb)2-) or an Al antisite (Al(Sb)2-) is dominant, and the concentrations of vacancies are much smaller than the antisite concentrations. Ga(Sb)2- is dominant in GaSb equilibrated with a Sb-rich solution, but the concentration of Sb antisites comes close to that of Ga(Sb)2- as temperature is lowered. For x larger than 0.6, a group-III vacancy is the predominant defect in the case of Sb-rich solutions. Calculated net acceptor concentrations agree well with those determined experimentally. A complex defect composed of Ga(Sb) and a Ga vacancy, which have been taken as the dominant residual acceptor, is expected to be negligible.