Aluminum-oxide films deposited as gate dielectrics on germanium （Ge） by atomic layer deposition were post oxidized in an ozone atmosphere. No additional interfacial layer was electron microscopy and X-ray photoelectron spectroscopy detected by the high-resolution cross-sectional transmission measurements made after the ozone post oxidation （OPO） treatment. Decreases in the equivalent oxide thickness of the OPO-treated Al2O3/Ge MOS capacitors were confirmed. Furthermore, a continuous decrease in the gate leakage current was achieved with increasing OPO treatment time. The results can be attributed to the film quality having been improved by the OPO treatment.
