An AlxTi1-xOy (ATO) film grown by atomic layer deposition exhibited an abrupt current jump with the applied electric field in current-voltage measurement. The ATO device also exhibited a negative differential resistance property, which may be due to the abrupt change of carrier number or mobility. Additionally, when a voltage was applied on the ATO device connected to a resistor in series, the voltage of the ATO was regulated at a constant value. This result suggests that the ATO device can be applicable as a good voltage regulator. (C) 2008 The Electrochemical Society.