EFFECTS OF ANNEALING INP(110) SURFACES ON SCHOTTKY-BARRIER HEIGHTS AT PD/INP(110) INTERFACES

The InP(110) surface becomes phosphorus deficient with increasing annealing temperature up to 200-degrees-C and recovers nearly the initial stoichiometry at about 350-degrees-C. The Schottky barrier heights formed on these annealed surfaces using Pd show a good correlation with the phosphorus loss from the surface due to annealing. This band-bending study using photoemission spectroscopy suggests the following: (i) Annealing creates donor defects due to phosphorus loss form the surface with a level at about 0.6 eV above the valence-band maximum (VBM); (ii) Pd deposition on InP (110) creates some other defects at around 0.9 eV above the VBM as usual; (iii) the surface Fermi-level positions ranging from 0.62 to 0.9 eV above the VBM are determined by the balance of these interface defect-state densities.