Abstract: A chemical sensor (10) is formed in part by depositing a stack of dielectric and resistive layers (13-15) on a support substrate (11). A cavity (17) is then formed on a substrate (16) to provide thermal isolation to the chemical sensor (10). The stack of dielectric and resistive layers (13-15) is then bonded to the substrate (16) and the support substrate (11) is removed. A layer of chemical sensing material (30) is then formed on the uppermost dielectric layer (15). Openings (33) may be formed through the stack of dielectric and resistive layers (13-15) to further enhance the thermal isolation of the chemical sensor (10) from the substrate (16).

Abstract: A method for forming a semiconductor sensor device comprises providing a substrate (4) and forming a sacrificial layer (18) over the substrate. The sacrificial layer (18) is then patterned and etched to leave a portion (19) on the substrate (4). A first isolation layer (6) is formed over the substrate (4) and portion (19) of the sacrificial layer and a conductive layer (12), which provides a heater for the sensor device, is formed over the first isolation layer (6). The portion (19) of the sacrificial layer is then selectively etched to form a cavity (10) between the first isolation layer (6) and the substrate (4), the cavity (10) providing thermal isolation between the heater and the substrate.

Abstract: A semiconductor chemical sensor device (2) comprises a sensitive layer (4) for detecting specific chemicals and a heater for heating the sensitive layer, which is formed by a heater portion (6) of a conductive layer (8) in the semiconductor chemical sensor device (2). The semiconductor chemical sensor device (2) further comprises a thermocouple (12) for detecting the temperature of the sensitive layer (4), the thermocouple comprising a P/N junction (14) formed as part of or adjacent the heater portion (6) of the conductive layer (8) such that a signal developed across the P/N junction (14) is representative of the temperature of the sensitive layer (4).

Abstract: A semiconductor device (50) comprises a semiconductor base, a heater (20) formed over the semiconductor base from conductive material, such as polysilicon, and a layer (22) for heating by the heater. The heater (20) comprises first (24) and second (26) arms extending over the semiconductor base from a heater portion (28) and an opening (34) extending vertically through the heater portion (28). A first heater contact (30) is coupled to an end of the first arm (24) and a second heater contact (32) is coupled to an end of the second arm (26). The layer (22) is formed over the opening (34) and heater portion (28) such that a vertical axis through the center (36) of the opening (34) extends through the center (36) of the layer (22).