Operating method of image sensor

Patent metadata

Field	Value
Publication number	US-9749567-B2
Application number	US-201514953411-A
Country	US
Kind code	B2
Filing date	Nov 29, 2015
Priority date	Nov 29, 2015
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

An operating method of an image sensor includes the following steps. The image sensor includes at least one pixel unit. The pixel unit includes a photoelectric conversion unit, a first control unit, a capacitor unit, and a sensing unit. The photoelectric conversion unit includes a quantum film photoelectric conversion unit, and the first control unit includes an oxide semiconductor transistor. The capacitor unit is coupled to the first control unit, and the sensing unit is configured to sense signals at a sense point coupled between the first control unit and the sensing unit. The pixel unit is discharged before a readout operation. The capacitor unit is charged by electrons emitted from the photoelectric conversion unit when the photoelectric conversion unit is excited by light. Signals at the sense point are then sensed by the sensing unit.

First claim

What is claimed is:

1. An operating method of an image sensor, comprising:
providing an image sensor, the image sensor comprising:
at least one pixel unit, the pixel unit comprising:
a photoelectric conversion unit, wherein the photoelectric conversion unit comprises a quantum film photoelectric conversion unit;
a first control unit, wherein the first control unit comprises an oxide semiconductor transistor, and a drain of the first control unit is connected to ground;
a capacitor unit coupled to the first control unit;
a sensing unit configured to sense signals at a sense point coupled between the first control unit and the capacitor unit; and
a second control unit coupled between the photoelectric conversion unit and the sensing unit, wherein the second control unit comprises an oxide semiconductor transistor configured to control a charging condition of the capacitor unit, and the sensing unit comprises a transistor having a gate directly connected with a drain of the oxide semiconductor transistor of the second control unit, wherein one end of the capacitor unit is coupled between the first control unit and the second control unit, and the other end of the capacitor unit is connected to the drain of the first control unit;

discharging the pixel unit by the first control unit before a readout operation;
charging the capacitor unit by electrons emitted from the photoelectric conversion unit when the photoelectric conversion unit is excited by light; and
sensing the signals at the sense point by the sensing unit.

2. The operating method of claim 1 , further comprising:
discharging the pixel unit by the first control unit and the second control unit before the readout operation; and
turning off the second control unit after the capacitor unit is charged by the electrons emitted from the photoelectric conversion unit.

3. The operating method of claim 2 , wherein the signals at the sense point are sensed after the second control unit is turned off.

4. The operating method of claim 1 , wherein the gate of the sensing unit is coupled between the first control unit and the second control unit.

5. The operating method of claim 1 , wherein the gate of the sensing unit is coupled to the sensing point.

6. The operating method of claim 5 , wherein the gate of the sensing unit is coupled between the capacitor unit and the first control unit.

7. The operating method of claim 1 , wherein the first control unit, the capacitor unit, and the sensing unit are disposed under the photoelectric conversion unit.

8. The operating method of claim 7 , wherein the image sensor further comprises a micro lens structure disposed on the photoelectric conversion unit.

9. The operating method of claim 7 , wherein the image sensor further comprises a color filter disposed on the photoelectric conversion unit.

10. The operating method of claim 1 , wherein the sensing unit comprises a silicon semiconductor transistor or an oxide semiconductor transistor.

11. The operating method of claim 1 , wherein the oxide semiconductor transistor of the first control unit and the oxide semiconductor transistor of the second control unit comprise indium gallium zinc oxide (IGZO) transistors.

12. An operating method of an image sensor, comprising:
providing an image sensor, the image sensor comprising:
at least one pixel unit, the pixel unit comprising:
a photoelectric conversion unit, wherein the photoelectric conversion unit comprises a quantum film photoelectric conversion unit;
a first control unit, wherein the first control unit comprises an oxide semiconductor transistor;
a capacitor unit coupled to the first control unit, wherein the capacitor unit is neither a transistor nor a part of a transistor; and
a sensing unit configured to sense signals at a sense point coupled between the first control unit and the capacitor unit, wherein one end of the capacitor unit is directly connected with and coupled to the photoelectric conversion unit, and the other end of the capacitor unit is coupled to the first control unit;

discharging the pixel unit by the first control unit before a readout operation;
charging the capacitor unit by electrons emitted from the photoelectric conversion unit when the photoelectric conversion unit is excited by light; and
sensing the signals at the sense point by the sensing unit.

Assignees

• United Microelectronics Corp

Inventors

• Zhou Zhibiao
• Lin Chen-Bin
• Chen Ding-Lung

Classifications

• H04N25/77

  Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components · CPC title

• H04N25/76 Primary

  Addressed sensors, e.g. MOS or CMOS sensors · CPC title

• H04N9/04

  Electricity · mapped topic

• H04N5/374 Primary

  Electricity · mapped topic

• H01L31/035218

  Electricity · mapped topic