Photoelectric conversion device and manufacturing method thereof

• US 20060261253A1
• Filed: 05/18/2006
• Published: 11/23/2006
• Est. Priority Date: 05/23/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Nishi, Kazuo, Arao, Tatsuya, Sugawara, Yuusuke, Hirose, Atsushi
• Granted Patent: US 7,705,283 B2
• Time in Patent Office: Days
• US Class Current: 250/214.100
• CPC Class Codes: G01J 1/18 using comparison with a reference electric value
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G01J 2001/4406 Plural ranges in circuit, e.g. switchable ranges; Adjusting sensitivity selecting gain values
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14692 Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 31/101 Devices sensitive to infrared, visible or ultraviolet radiation
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

It is an object to provide a photoelectric conversion device which detects light ranging from weak light to strong light. The present invention relates to a photoelectric conversion device having a photodiode having a photoelectric conversion layer, an amplifier circuit including a thin film transistor and a bias switching means, where a bias which is connected to the photodiode and the amplifier circuit is switched by the bias switching means when intensity of incident light exceeds predetermined intensity, and accordingly, light which is less than the predetermined intensity is detected by the photodiode and light which is more than the predetermined intensity is detected by the thin film transistor of the amplifier circuit. By the present invention, light ranging from weak light to strong light can be detected.

Claims

1. A photoelectric conversion device comprising:

a photodiode comprising a photoelectric conversion layer;

an amplifier circuit comprising a thin film transistor; and

a bias switching circuit;

wherein a bias which is connected to the photodiode and the amplifier circuit is switched by the bias switching circuit at a predetermined intensity of incident light, and light which is less than the predetermined intensity is detected by the photodiode and light which is more than the predetermined intensity is detected by the thin film transistor of the amplifier circuit.

2. The photoelectric conversion device according to claim 1, wherein the photoelectric conversion layer comprising a p-type semiconductor layer, an i-type semiconductor layer and an n-type semiconductor layer.

3. The photoelectric conversion device according to claim 1, wherein the thin film transistor comprising a source region or a drain region, a channel formation region, a gate insulating film and a gate electrode.

4. The photoelectric conversion device according to claim 1, wherein the photodiode and the amplifier circuit are formed over a light-transmitting substrate.

5. The photoelectric conversion device according to claim 1, wherein a direction of incident light which is detected by the photodiode is the same as a direction of incident light which is detected by the thin film transistor.

6. The photoelectric conversion device according to claim 1, wherein the thin film transistor is a top gate thin film transistor.

7. The photoelectric conversion device according to claim 1, wherein a direction of incident light which is detected by the photodiode and a direction of incident light which is detected by the thin film transistor are opposite to each other, with a substrate as the center.

8. The photoelectric conversion device according to claim 1, wherein the thin film transistor is a bottom gate thin film transistor.

9. A method for driving a photoelectric conversion device comprising:

a photodiode having a photoelectric conversion layer;

an amplifier circuit including a thin film transistor; and

a bias switching circuit;

the method comprising the steps of;

switching a bias which is connected to the photodiode and the amplifier circuit by the bias switching circuit at a predetermined intensity of the incident light, and

detecting light which is less than the predetermined intensity by the photodiode or light which is more than the predetermined intensity by the thin film transistor of the amplifier circuit.

10. The method for driving a photoelectric conversion device according to claim 9, wherein the photoelectric conversion layer comprising a p-type semiconductor layer, an i-type semiconductor layer and an n-type semiconductor layer.

11. The method for driving a photoelectric conversion device according to claim 9, wherein the thin film transistor has a source electrode or a drain electrode, a channel formation region, a gate insulating film and a gate electrode.

12. The method for driving a photoelectric conversion device according to claim 9, wherein the photodiode and the amplifier circuit are formed over a light-transmitting substrate.

13. The method for driving a photoelectric conversion device according to claim 9, wherein a direction of incident light which is detected by the photodiode is the same as a direction of incident light which is detected by the thin film transistor.

14. The method for driving a photoelectric conversion device according to claim 9, wherein a direction of incident light which is detected by the photodiode and a direction of incident light which is detected by the thin film transistor are opposite to each other, with a substrate as the center.

15. A photoelectric conversion device comprising:

a photo integrated circuit comprising a first photo sensor, a second photo sensor;

a switch;

a first bias; and

a second bias.

16. The photoelectric conversion device according to claim 15, wherein the first photo sensor is photodiode.

17. The photoelectric conversion device according to claim 15, wherein the second photo sensor is an amplifier circuit.