US 12,249,663 B2
Thin film transistor based light sensor
Shih-Llen Linus Lu, Hsinchu (TW); and Katherine H. Chiang, New Taipei (TW)
Assigned to Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed on Aug. 30, 2021, as Appl. No. 17/461,211.
Prior Publication US 2023/0063673 A1, Mar. 2, 2023
Int. Cl. G08B 13/189 (2006.01); H01L 31/02 (2006.01); H01L 31/0203 (2014.01); H01L 31/0272 (2006.01); H01L 31/101 (2006.01)
CPC H01L 31/02019 (2013.01) [G08B 13/1895 (2013.01); H01L 31/0203 (2013.01); H01L 31/0272 (2013.01); H01L 31/101 (2013.01)] 20 Claims
OG exemplary drawing
 
1. 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.