Solid state optical imaging pixel with resistive load
AssigneeSTMicroelectronics S.r.l.
InventorsAlexander Kalnitsky, Frank Randolph Bryant, Marco Sabatini
Life of this patent
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Abstract
Disclosed is a CMOS image sensor that includes pixels employing a radiation-sensitive resistive element in which the resistance of the element changes in response to the quantity of radiation striking it. The resistive elements are made from an appropriately doped polycrystalline semiconductor material such as polysilicon. The pixels are provided on a semiconductor device in which the photosensitive resistive elements are provided on a first layer and the pixel associated transistors are provided on a second layer. The fill factor may be approach 100 percent for such pixels.
Claims27
A photosensitive pixel formed on a semiconductor substrate, the pixel comprising:
- (a) at least one access transistor located at a first layer of the semiconductor substrate;
- and
- (b) a radiation-sensitive resistive element located at a second layer of the semiconductor substrate and coupled to said access transistor, wherein the radiation-sensitive resistive element has an exposed surface accessible to radiation, and wherein the radiation-sensitive resistive element undergoes a change in resistance when exposed to radiation of a defined intensity
- wherein the first layer of the semiconductor substrate having the at least one access transistor is below the second layer of the semiconductor substrate having the radiation-sensitive element.
An imager comprising an array of detectors for providing output signals indicative of physical stimuli to which the one or more detectors has been exposed, wherein at least one of the detectors comprises:
- (a) at least one access transistor located at a first layer of a semiconductor structure;
- and
- (b) a radiation-sensitive resistive element located at a second layer of the semiconductor structure and coupled to the access transistor, wherein the radiation-sensitive resistive element has an exposed surface accessible to radiation, and wherein the radiation-sensitive resistive element undergoes a change in resistance when exposed to radiation of a defined intensity
- wherein the first layer having the at least one access transistor is below the second level having the radiation-sensitive element.
A system for producing an image of an object, the system comprising:
- (a) an array of detectors for providing output signals indicative of physical stimuli to which the one or more detectors has been exposed, wherein at least one of the detectors comprises:
- (i) an access transistor located at a first layer of a semiconductor structure, and
- (ii) a radiation-sensitive resistive element located at a second layer of the semiconductor structure and coupled to the access transistor, wherein the radiation-sensitive resistive element has an exposed surface accessible to radiation, and wherein the radiation-sensitive resistive element undergoes a change in resistance when exposed to radiation of a defined intensity;
- and
- (b) an output device for outputting an image resulting from the outputs of the array of detectors
- wherein the first layer having the access transistor is below the second level having the radiation-sensitive element.
Dependencies are inferred from the claim text.