PHOTODIODE, LIGHT SENSOR DEVICE AND FABRICATING METHOD THEREOF

• US 20120261656A1
• Filed: 03/29/2012
• Published: 10/18/2012
• Est. Priority Date: 04/15/2011
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: SHU, Fang-An, TSAI, Yao-Chou, SHINN, Ted-Hong
• Granted Patent: US 8,987,856 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: H01L 31/022483 composed of zinc oxide [ZnO]
• CPC Class Codes: H01L 31/032 including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 31/108 the potential barrier being of the Schottky type

Abstract

A photodiode, a light sensor and a fabricating method thereof are disclosed. An n-type semiconductor layer and an intrinsic semiconductor layer of the photodiode respectively comprise n-type amorphous indium gallium zinc oxide (IGZO) and intrinsic IGZO. The oxygen content of the intrinsic amorphous IGZO is greater than the oxygen content of the n-type amorphous IGZO. A light sensor comprise the photodiode is also disclosed.

Claims

1. A photodiode, comprising:

a substrate;

a lower electrode disposed on the substrate;

a N-type semiconductor layer disposed on the lower electrode, wherein the N-type semiconductor layer comprises a N-type amorphous indium gallium zinc oxide (IGZO) layer;

an intrinsic semiconductor layer disposed on the N-type semiconductor layer, wherein the intrinsic semiconductor layer comprises an intrinsic amorphous indium gallium zinc oxide (IGZO) layer, and the oxygen content of the N-type amorphous IGZO layer is higher than the oxygen content of the intrinsic amorphous IGZO layer; and

an upper electrode disposed on the intrinsic semiconductor layer.

2. The photodiode of claim 1, further comprising a P-type semiconductor layer disposed between the intrinsic semiconductor layer and the upper electrode, wherein a material of the P-type semiconductor layer is aluminum nitride zinc oxide (AlNZnO_x), aluminum zinc oxide (AlZnO_x), lithium zinc oxide (LiZnO_x), arsenic zinc oxide (AsZnO_x), or antimony zinc oxide (SbZnO_x).

3. The photodiode of claim 2, wherein a thickness of the P-type semiconductor layer is about 300-5000 Å

.

4. The photodiode of claim 1, wherein a thickness of the N-type semiconductor layer is about 300-5000 Å

.

5. The photodiode of claim 1, wherein a thickness of the intrinsic semiconductor layer is about 1-5 μ

m.

10. A method of fabricating the photodiode of the claim 1, the method comprising:

providing a sputtering target made by a mixture comprising indium oxide, gallium oxide, and zinc oxide; and

performing a sputtering process under an atmosphere containing oxygen and argon to continuously form the N-type semiconductor layer and the intrinsic semiconductor layer, wherein the flow rate ratio of the oxygen to the argon for depositing the N-type semiconductor layer is smaller than the flow rate ratio of the oxygen to the argon for depositing the intrinsic semiconductor layer.

11. The method of claim 10, wherein the flow rate ratio of the oxygen to the argon for depositing the N-type semiconductor layer is 0-0.15.

12. The method of claim 10, wherein the flow rate ratio of the oxygen to the argon for depositing the intrinsic semiconductor layer is 0.02-0.7.

6. A light sensor, comprising:

a thin film transistor (TFT) on a substrate, wherein the TFT comprises;

a gate on the substrate;

a gate dielectric layer covering the gate and the substrate;

a channel layer disposed on the gate dielectric layer and right above the gate; and

a source and a drain respectively disposed on two opposite ends of the channel layer; and

a photodiode disposed on the drain, wherein the photodiode comprises;

a N-type semiconductor layer disposed on the drain, wherein the N-type semiconductor layer comprises a N-type amorphous indium gallium zinc oxide (IGZO);

an intrinsic semiconductor layer disposed on the N-type semiconductor layer, wherein the intrinsic semiconductor layer comprises an intrinsic amorphous indium gallium zinc oxide (IGZO), and the oxygen content of the N-type amorphous IGZO is greater than the oxygen content of the intrinsic amorphous IGZO; and

an upper electrode disposed on the intrinsic semiconductor layer.

7. The light sensor of claim 6, wherein the photodiode further comprises a P-type semiconductor layer disposed between the intrinsic semiconductor layer and the upper electrode.

8. The light sensor of claim 7, wherein a material of the P-type semiconductor layer is aluminum nitride zinc oxide (AlNZnO_x), aluminum zinc oxide (AlZnO_x), lithium zinc oxide (LiZnO_x), arsenic zinc oxide (AsZnO_x), or antimony zinc oxide (SbZnO_x).

9. The light sensor of claim 6, further comprising:

a protection layer covering the source, the drain, and the channel, but exposing the photodiode; and

a conductive layer disposed on the protection layer and connecting the upper electrode of the photodiode.