Fet and fiber based sensor
AssigneeHoneywell International Inc.
InventorsCornel P. Cobianu, Bogdan-Catalin Serban, Viorel Georgel Dumitru, Octavian Buiu, Alisa Stratulat, Mihai Brezeanu
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Abstract
A gas sensor includes a field effect transistor supported on an oxide layer of a substrate, the field effect transistor having a doped source (p+ doped for T-FET and n+ doped for FET) and an n+ doped drain separated by an channel region (intrinsic for T-FET or slightly p-doped for FET), and a floating gate separated from the channel region by a gate oxide, a passivation layer covering the floating gate, and a sensing layer supported by the passivation layer, the sensing layer comprising nanofibers.
Claims20
A method comprising:
- exposing a nanofiber sensing layer of a field effect transistor-based gas sensor to a gas that changes a capacitance and work function of the sensing layer and hence current through a channel of the field effect transistor;
- obtaining a drain voltage of a reference sensor having the same construction as the gas sensor with the addition of a blocking layer blocking the gas from the nanofiber sensing layer of the reference sensor;
- and
- amplifying a difference in drain voltages of the gas sensor and reference sensor to obtain an output signal representative of exposure of the nanofiber sensing layer to the gas.
A method comprising:
- exposing a first nanofiber sensing layer of a field effect transistor-based gas sensor to a gas that changes a capacitance and work function of the sensing layer and hence current through a channel of the field effect transistor;
- obtaining a first drain voltage of the gas sensor;
- preventing exposure of a second nanofiber sensing layer of a field effect transistor-based reference sensor to the gas, wherein the reference sensor has a same construction as the gas sensor with the addition of a block layer blocking the gas from the second nanofiber sensing layer of the reference sensor;
- obtaining a second drain voltage of the reference sensor;
- and
- amplifying a difference in drain voltages of the gas sensor and reference sensor to obtain an output signal representative of exposure of the nanofiber sensing layer to the gas.
A method comprising:
- exposing a nanofiber sensing layer of a field effect transistor-based gas sensor, wherein the field effect transistor is supported on an oxide layer of a substrate, the field effect transistor having a doped source and an n+ doped drain separated by an intrinsic channel region, and a floating gate separated from the channel region by a gate oxide, a passivation layer covering the floating gate, to a gas that changes a capacitance and work function of the sensing layer and hence current through a channel of the field effect transistor;
- applying a gate bias such that electron accumulation occurs in the intrinsic channel region and current flows across the channel;
- and
- detecting a change in the capacitance and work function based on the gas reacting with the sensing layer.
Dependencies are inferred from the claim text.