Hydrogenation of GaAs-on-Si: Effects on diode reverse leakage current.

Plasma hydrogenation of MOCVD-grown GaAs-on-Si increases the reverse breakdown voltage of Schottky diode structures by a factor of three. The reverse bias leakage current of simple TiPtAu diodes fabricated on this material appears to be dominated by the high density (~ 10 sup 8 cm sup (-2)) of threading dislocations caused by the large (4%) lattice mismatch between GaAs and Si. Exposure to a hydrogen plasma at 250C for 3 h allows atomic hydrogen to passivate dangling bonds associated with these line defects in the GaAs, lowering the generation-recombination contribution to the reverse leakage current. A reduced Schottky barrier height on hydrogenated samples is consistent with As depletion of the surface during the plasma processing.