HYDROGEN PASSIVATION OF DISLOCATIONS IN INP ON GAAS HETEROSTRUCTURES

The effects of hydrogenation on the properties of Zn-doped InP/GaAs heterostructures grown by metalorganic chemical vapor deposition were studied by current-voltage (I-V), deep level transient spectroscopy (DLTS), 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 corresponding reduction in total trap concentration from approximately 6 x 10(14) to approximately 3 x 10(12) cm-3 at a depth of approximately 1.5 mum below the surface. The Zn dopants were completely reactivated by a subsequent 5 min 400-degrees-C anneal without degradation of the reverse current or reactivation of the deep levels. Anneals in excess of 580-degrees-C were necessary to reactivate the deep levels and degrade the leakage current to their original values, indicating the passivation of threading dislocations by hydrogen, and the existence of a wide temperature window for post-passivation processing.