Patent ID: 6111280
Filing Date: 2000-08-29
Classification: G01N

Abstract:
A gas-sensing semiconductor device comprising a semiconductor substrate (2), a thin insulating layer (3) on one side of the substrate, and a thin semiconductor layer (4) on top of the thin insulating layer, wherein the device includes at least one sensing area in which the material of the substrate has been removed to leave a membrane (20) formed by the thin insulating layer and the thin semiconductor layer, and wherein the at least one sensing area is provided with a gas-sensitive layer (18, 43) and a heater (6, 42, 52, 62, 73, 83) for heating the gas-sensitive layer to promote gas reaction with the gas-sensitive layer, and a sensor (16, 42, 72, 82) for providing an electrical output indicative of gas reaction with the gas-sensitive layer, characterised in that the at least one sensing area incorporates a MOSFET formed in the thin semiconductor layer (4) and forming part of the heater and/or sensor.