Electronical properties of metal-insulator-semiconductor devices prepared on thermally treated InP in phosphorus overpressure

The effect of excess phosphorus vapor during the process of MIS structures on InP is analyzed in detail. It is shown that the density of interface state distribution is considerably modified after in situ thermal precleaning of the substrate in phosphorus overpressure (suppression of the Fermi-level pinning and significant reduction of the density of surface states near midgap). Phosphorus overpressure also provides an efficient protection of the surface during the insulator deposition. Fermi-level pinning in the upper part of the gap is assigned to the uncontrolled native oxide left on the surface after a stay of InP substrate in ambient atmosphere.