Gas sensor, used for monitoring hydrogen, oxygen, hydrocarbons and carbon monoxide concentrations in exhaust gas, has HEMT structure, in which semiconductor layers form heterogeneous layer sequence

摘要

Gas sensor comprises a sequence of semiconductor layers (11, 15, 16, 17); a source (12) and a drain (13) for measuring the current; and a gate layer (14) for producing a potential depending on a gas concentration to be measured. The sensor has an HEMT structure, in which the semiconductor layers form a heterogeneous layer sequence of different materials which form a two dimensional electron gas. Preferred Features: The gate layer is made of precious metals, metal oxides and/or zeolites, preferably platinum. The semiconductor layers are formed from a group III nitride heterostructure, preferably AlGaN alternating with GaN. The sensor is formed as a MESFET or MOSFET. An additional insulating layer made of SiO2, AlN, Si3N4 and/or silicon oxynitride. A p-conducting layer made of GaN, AlGaN or AlN is arranged below the gate layer.