High-barrier height metal-insulator-semiconductor diodes on n-InP

Metal-insulator-semiconductor diodes were fabricated using Pd, Ni, and Au contacts on n-InP covered by a 40-Å chemically grown oxide. The oxide had a refractive index of 1.4-1.6 with a composition of mainly In₂O ₃+some InPO₃ near the surface and mixed oxide+InP near the interface. Pd devices gave the highest-barrier height of 0.80 eV and the lowest reverse saturation current density of 3×10^-8 A/cm². Current-voltage-temperature and capacitance-voltage- temperature data gave temperature dependence of barrier height and revealed an interface state recombination current mechanism with surface states 0.4 eV above the valence-band level. Richardson plots gave good straight lines when empirically corrected using barrier height divided by ideality factor.