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US 2006/0154401 A1Published application
Gas-sensing semiconductor devices
AssigneeUniversity of Warwick
InventorsJulian Gardner, James Covington, Florin Udrea
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AssigneeUniversity of Warwick
InventorsJulian Gardner, James Covington, Florin Udrea
Estimating the term…
A gas-sensing semiconductor device is fabricated on a silicon substrate having a thin silicon oxide insulating layer in which a resistive heater made of a CMOS compatible high temperature metal is embedded. The high temperature metal is tungsten. The device includes at least one sensing area provided with a gas-sensitive layer separated from the heater by an insulating layer. As one of the final fabrication steps, the substrate is back-etched so as to form a thin membrane in the sensing area. Except for the back-etch and the gas-sensitive layer formation, that are carried out post-CMOS, all other layers, including the tungsten resistive heater, are made using a CMOS process employing tungsten metallisation. The device can be monolithically integrated with the drive, control and transducing circuitry using low cost CMOS processing. The heater, the insulating layer and other layers are made within the CMOS sequence and they do not require extra masks or processing.
A smart sensor according to claim 27, comprising a semiconductor substrate, wherein the gas-sensing device has at least one sensing area provided with a gas-sensitive layer to be heated by the heater to promote gas, and sensing means for providing an electrical output indicative of gas reaction with the gas-sensitive layer.
A smart sensor according to claim 27, wherein the heater is a meander-shaped tungsten heater.
A gas-sensing semiconductor device comprising a semiconductor substrate, at least one sensing area provided with a gas-sensitive layer and a heater for heating the gas-sensitive layer to promote gas reaction with the gas-sensitive layer, and a sensor for providing an electrical output indicative of gas reaction with the gas-sensitive layer, wherein the heater has in its composition at least one layer of tungsten and comprises two or more heating layers.
A smart sensor according to claim 27, wherein the heater incorporates a spreading plate.
A gas-sensing semiconductor device comprising a semiconductor substrate, at least one sensing area provided with a gas-sensitive layer and a heater for heating the gas-sensitive layer to promote gas reaction with the gas-sensitive layer, and a sensor for providing an electrical output indicative of gas reaction with the gas-sensitive layer, wherein the heater has in its composition at least one layer of tungsten, and wherein the sensor incorporates laterally spaced tungsten electrodes in the vicinity of the gas-sensitive layer.
A smart sensor according to claim 27, which has been produced utilising CMOS, Bi-CMOS or SOI CMOS processing steps, or Bi-CMOS processing steps followed by a post-CMOS back-etch.
A smart sensor according to claim 27, which is a resistive gas-sensing device.
A smart sensor according to claim 27, which is a calorimetric gas-sensing device.
(canceled)
A smart sensor comprising a gas-sensing device monolithically integrated with an electronic circuit for drive, control and transducing functions, wherein tungsten is used both as a metallisation layer for contacts and interconnects in the electronic circuit and to form a heater of the gas-sensing device.
Dependencies are inferred from the claim text.