Al2O3/InP structure with less oxides of InP fabricated by helicon-volume excited O-2-Ar plasma treatment of Al/InP

Al2O3/n-InP (100) structure was fabricated by helicon-wave excited O-2-Ar p lasma treatment of an Al/InP substrate. The capacitance-voltage (C-V) and c onductance-voltage (G-V) characteristics were measured to evaluate the elec trical quality of the Al2O3/InP interface. X-ray photoelectron spectroscopi c (XPS) measurements were performed to investigate the chemical composition and depth profile. Reasonably good C-V characteristics were obtained when the Bow-rate ratios of Ar were 30% and 40%. XPS data indicated that Al2O3 w as uniformly formed along the whole film thickness. Oxides of In (In2O3) an d InP InPO3, In(PO3) and In(PO4) were scarcely observed in the film and at the interface with the InP substrate, probably due to the reductioning effe ct of AL The absence of the oxides is one of the reasons for the reasonably good C-V characteristics.