Native oxide formation and electrical instabilities at the insulator/InP interface

A variety of surface analytical techniques have been employed in an attempt to correlate the chemistry of InP native oxides with electrical interface instabilities observed in InP MIS devices. The native oxides examined were predominantly InPO4 but upon closer examination had small amounts of In2O3 incorporated into the outer oxide surface. The band gap of InPO4 was estimated to be about 4.5 eV, although several observations indicate that this may be only a lower limit. It is suggested that tunneling of electrons from InP through the InPO4 into In2O3 may account for electrical interface instabilities observed in InP MIS devices.