Thin film transistor based light sensor
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsShih-Llen Linus Lu, Katherine H. Chiang
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Abstract
The present disclosure describes an embodiment of a thin film transistor based light sensor circuit. The thin film transistor based light sensor circuit includes two thin film transistors, in which a channel region of one of the thin film transistors includes a light sensing area and a channel region of the other thin film transistor has a capping material disposed thereon. The thin film transistor based light sensor circuit further includes a comparator device electrically coupled to the two thin film transistors and configured to detect a current difference between the thin film transistors in response to the thin film transistor with the channel region having the light sensing area being exposed to light.
Claims20
A circuit, comprising:
- a first transistor with a first channel region, a first source/drain region disposed on a first end portion of the first channel region, and a second source/drain region disposed on a second end portion of the first channel region, wherein the first channel region comprises a light sensing area between the first and second end portions of the first channel region;
- a first capacitor directly coupled to the first source/drain region of the first transistor;
- a second transistor with a second channel region, a third source/drain region disposed on a first end of the second channel region, a fourth source/drain region disposed on a second end of the second channel region, wherein the second channel region comprises a middle portion between the first and second end portions of the second channel region;
- a second capacitor directly coupled to the third source/drain region of the second transistor;
- a capping material over the middle portion of the second channel region;
- and
- a comparator device electrically coupled to the first source/drain region of the first transistor and the third source/drain region of the second transistor and configured to detect a current difference between the first and second transistors in response to the first transistor being exposed to light.
An integrated circuit structure, comprising:
- a device layer, comprising
- a comparator device formed on a substrate;
- and
- a thin film transistor device layer disposed on the device layer, wherein the thin film transistor device layer comprises:
- a first thin film transistor that comprises a first channel region, a first source/drain region disposed on a first end portion of the first channel region, and a second source/drain region disposed on a second end portion of the first channel region, and wherein the first channel region comprises a light-receiving area between the first and second end portions of the first channel region;
- a first capacitor directly coupled to the first source/drain region of the first thin film transistor;
- a second thin film transistor that comprises a second channel region, a third source/drain region disposed on a first end of the second channel region, a fourth source/drain region disposed on a second end of the second channel region, and wherein the second channel region comprises a middle portion between the first and second end portions of the second channel region;
- a second capacitor directly coupled to the third source/drain region of the second thin film transistor;
- a capping material over the middle portion of the second channel region;
- and
- an interconnect structure arranged to electrically couple the first and second thin film transistors to the comparator device.
A circuit, comprising:
- a first transistor comprising a first channel region with a light sensing area;
- a first capacitor directly coupled to the first transistor;
- a second transistor with a second channel region;
- a second capacitor directly coupled to the second transistor;
- a capping material over the second channel region;
- and
- a comparator device electrically coupled to the first and second transistors and configured to detect a current difference between the first and second transistors in response to the first transistor being exposed to light.
Dependencies are inferred from the claim text.