Patent ID: 7578974

Claim:
A resistance-type oxygen sensor, comprising: an oxygen gas detection part made of an oxide semiconductor, wherein the oxide semiconductor is an oxide comprising cerium ions and hafnium ions, the amount of the cerium ions as a percentage of the amount of positive ions in the oxide semiconductor is 60 mol % or greater, the hafnium ions are in a solid solution in a parent phase of said oxide semiconductor, the amount of the hafnium ions as a percentage of the amount of the positive ions in said oxide semiconductor is 3 to 30 mol %, the conductivity of the oxygen gas detection part made of the oxide semiconductor is at least 1×10 −4 S/cm at 600° C., and the oxide semiconductor has a film thickness of 50 μm or less, a resistance of 200 kΩ or less at 600° C. and an oxygen partial pressure of 1.8×10 4 Pa.