Sensor device with improved sensitivity to temperature variation in a semiconductor substrate
AssigneeAnalog Devices, Inc.
InventorLuke Alexander Pillans
Life of this patent
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Abstract
A sensor device formed on a semiconductor substrate. The device comprises a thermal radiation sensor including a sensing cell and a referencing cell which are co-operable for providing a first output signal indicative of the temperature fluctuation resulting from incident radiation. A gradient sensor including a pair of cells spatially located on the semiconductor substrate is provided which are co-operable to provide a second output signal indicative of the temperature gradient across the semiconductor substrate for facilitating calibrating the first output signal. At least one of the cells of the gradient sensor is not common to the cells of the thermal radiation sensor.
Claims28
An apparatus comprising a sensor device formed on a semiconductor substrate, the sensor device comprising:
- a thermal radiation sensor including an infrared radiation sensing cell and a first shielded infrared radiation referencing cell spatially separated from each other on the semiconductor substrate, the first shielded infrared radiation referencing cell and the infrared radiation sensing cell co-operating to provide a first output signal indicative of temperature fluctuations resulting from incident radiation, wherein the infrared radiation sensing cell is exposed to incident infrared radiation and the first shielded infrared radiation referencing cell is shielded from incident infrared radiation;
- and
- a gradient sensor including a second shielded infrared radiation referencing cell and at least one of the first shielded infrared radiation referencing cell or a third shielded infrared radiation referencing cell, wherein the gradient sensor is configured to provide a second output signal indicative of a temperature gradient experienced by the thermal radiation sensor, wherein the cells of the gradient sensor are shielded from incident infrared radiation,
- wherein the second output signal is operably combined with the first output signal to effect a calibration of the first output signal.
A sensor device formed on a semiconductor substrate, the device comprising:
- a thermal radiation sensor including an infrared radiation sensing cell and a first shielded infrared radiation referencing cell configured to provide a first output signal indicative of temperature fluctuation resulting from incident radiation;
- a gradient sensor responsive to temperature changes on different portions of the substrate, the gradient sensor including a pair of shielded infrared radiation referencing cells spatially separated from each other on the semiconductor substrate, wherein at least one of the pair of shielded infrared radiation referencing cells comprises a second shielded infrared radiation referencing cell, the pair of shielded infrared radiation referencing cells configured to provide a second output signal indicative of a temperature gradient experienced by the thermal radiation sensor for facilitating calibrating the first output signal;
- and
- a calibration module configured to read the first and second output signals for calibrating the first output signal using the second output signal;
- wherein said infrared radiation sensing cell is configured to be exposed to incident infrared radiation and said pair of shielded infrared radiation referencing cells are configured to be shielded from incident infrared radiation.
A method of calibrating a sensor device for incident radiation, the sensor device including a thermal radiation sensor and a gradient sensor formed on a semiconductor substrate, the gradient sensor being responsive to temperature changes on different portions of the substrate, the method comprises the steps of:
- a. obtaining, from the thermal radiation sensor, a first output signal indicative of a temperature fluctuation resulting from an incident radiation, wherein the thermal radiation sensor includes an infrared radiation sensing cell and a first shielded infrared radiation referencing cell, wherein the infrared radiation sensing cell is exposed to incident radiation and the first shielded infrared radiation referencing cell is shielded from incident infrared radiation;
- b. obtaining, from the gradient sensor, a second output signal indicative of a temperature gradient experienced by the thermal radiation sensor, wherein the gradient sensor includes a pair of shielded infrared radiation referencing cells at least one of which is different from the first shielded infrared radiation referencing cell, wherein the pair of shielded infrared radiation referencing cells are shielded from the incident infrared radiation;
- and
- c. calibrating the first output signal with the second output signal.
Dependencies are inferred from the claim text.