EFFECT OF OXYGEN ON MINORITY-CARRIER LIFETIME AND RECOMBINATION CURRENTS IN SI1-XGEX HETEROSTRUCTURE DEVICES

A p+-i-n diode structure is presented which is suitable for determining the recombination lifetime in thin Si(1-x)Ge(x) layers grown on Si. Electrical measurements and computer simulations are used to extract carrier lifetimes in Si(1-x)Ge(x) layers with various oxygen concentrations. The minority-carrier lifetime increases dramatically as the oxygen concentration in the Si(1-x)Ge(x) decreases from 3 X 10(20) to less than 3 X 10(17) cm-3. Lifetimes extracted from the p+-i-n diodes are consistent with those obtained from measurements on heterojunction bipolar transistors with high oxygen concentrations in the Si1-xGex base.