HETERO JUNCTION TYPE GAS SENSOR

摘要

PURPOSE:To obtain a good sensing characteristic for a combustible gas by providing many gas introducing holes by etching to the joint surface of an n-type oxide semiconductor and p-type oxide semiconductor in such a manner that the gas contacts said surface. CONSTITUTION:The joint part is made of an Li-doped NiO film having 1mum thickness as the p-type oxide semiconductor 1 and a ZnO film having 2mum thickness as the n-type oxide semiconductor to a 1mmX2mm size and the gas introducing holes 3 sized 10mum square and 2mum depth are formed at 15mum pitch thereto by reactive ion etching from above the semiconductor 1. A positive bias voltage is impressed to such element in the forward direction of a diode formed of the semiconductors 1 and 2 to operate the same. The combustible gas reacts with gaseous oxygen adsorbed to the joint part when the gas arrives at the joint part of the semiconductors 1 and 2 through the holes 3. The electrostatic potential in the joint part is then changed and the current flowing in the joint part changes. As a result, the concn. of the cmbustible gas is known from the current flowing in the joint part.