HYDROGEN PASSIVATION OF DISLOCATIONS IN INP ON GAAS HETEROSTRUCTURES

The effects of hydrogenation on the properties of Zn-doped InP/GaAs he terostructures grown by metalorganic chemical vapor deposition were st udied by current-voltage (I-V), deep level transient spectroscopy (DLT S), and photoluminescence. Significant improvements in leakage current and breakdown voltage in InP diodes on GaAs were observed after a 2 h hydrogen plasma exposure at 250-degrees-C. DLTS indicated a correspon ding reduction in total trap concentration from approximately 6 x 10(1 4) to approximately 3 x 10(12) cm-3 at a depth of approximately 1.5 mu m below the surface. The Zn dopants were completely reactivated by a s ubsequent 5 min 400-degrees-C anneal without degradation of the revers e current or reactivation of the deep levels. Anneals in excess of 580 -degrees-C were necessary to reactivate the deep levels and degrade th e leakage current to their original values, indicating the passivation of threading dislocations by hydrogen, and the existence of a wide te mperature window for post-passivation processing.