Method of forming optical sensor

• US 8,361,818 B2
• Filed: 09/01/2010
• Issued: 01/29/2013
• Est. Priority Date: 05/16/2008
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Cho, An-Thung, Peng, Chia-Tien, Lin, Kun-Chih
• Primary Examiner(s): GREEN, TELLY D
• Application Number:
  US12/874,203
• Publication Number:
  US 20100330735A1
• Time in Patent Office: 881 Days
• Field of Search: 257/44, 257/290, 438/7, 438/16, 438/59, 438/686, 438/381, 438/26, 438/29
• US Class Current: 438/29
• CPC Class Codes: H01L 27/14667 Colour imagers
• CPC Class Codes: H01L 27/14692 Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon
• CPC Class Codes: H01L 31/0384 including other non-monocrystalline materials, e.g. semiconductor particles embedded in an insulating material H01L31/0392 takes precedence
• CPC Class Codes: H01L 31/03921 including only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A method of forming an optical sensor includes the following steps. A substrate is provided, and a read-out device is formed on the substrate. a first electrode electrically connected to the read-out device is formed on the substrate. a photosensitive silicon-rich dielectric layer is formed on the first electrode, wherein the photosensitive silicon-rich dielectric layer comprises a plurality of nanocrystalline silicon crystals. A second electrode is formed on the photosensitive silicon-rich dielectric layer.

Claims

1. A method of forming an optical sensor, comprising:

providing a substrate, and forming a read-out device on the substrate;

forming a first electrode electrically connected to the read-out device on the substrate;

forming a photosensitive silicon-rich dielectric layer on the first electrode, wherein the photosensitive silicon-rich dielectric layer comprises a plurality of nanocrystalline silicon crystals; and

forming a second electrode on the photosensitive silicon-rich dielectric layer.

2. The method of claim 1, wherein the first electrode comprises a metal electrode, and the second electrode comprises a transparent electrode.

3. The method of claim 1, wherein the nanocrystalline silicon crystal has a diameter substantially between 0.5 and 200 nanometers.

4. The method of claim 1, wherein the read-out device comprises a thin film transistor read-out device.

5. The method of claim 1, wherein the optical sensor comprises an ambient light sensor disposed in a non-display region of a display device.

6. The method of claim 1, wherein the photosensitive silicon-rich dielectric layer comprises a silicon-rich nitride layer having a molecular formula of SiNy, and y is greater than 0.1 and less than 1.33.

7. The method of claim 6, wherein forming the photosensitive silicon-rich dielectric layer comprises performing a plasma enhanced chemical vapor deposition process to deposit the silicon-rich nitride layer on the substrate.

8. The method of claim 7, wherein the plasma enhanced chemical vapor deposition process uses silane to react with a nitrogen source gas to form the silicon-rich nitride layer, and the ratio of the silane to the nitrogen source gas is substantially between 15 and 1.

9. The method of claim 8, wherein the nitrogen source gas comprises at least one of ammonia and nitrogen.

10. The method of claim 7, wherein the plasma enhanced chemical vapor deposition process is performed in a temperature range substantially between 250 and 400°

C.

11. The method of claim 1, wherein the photosensitive silicon-rich dielectric layer comprises a silicon-rich oxynitride layer having a molecular formula of SiOxNy, x is between 0.1 and 2, and y is between 0.1 and 1.33.

12. The method of claim 11, wherein forming the photosensitive silicon-rich dielectric layer comprises performing a plasma enhanced chemical vapor deposition process to deposit the silicon-rich oxynitride layer on the substrate.

13. The method of claim 11, wherein the plasma enhanced chemical vapor deposition process uses silane to react with a nitrogen-oxygen source gas to form the silicon-rich oxynitride layer, and the ratio of the silane to the nitrogen-oxygen source gas is substantially between 5 and 0.3.

14. The method of claim 13, wherein the nitrogen-oxygen source gas comprises nitrous oxide (N₂O).

15. The method of claim 14, wherein the nitrogen-oxygen source gas comprises at least one of ammonia, nitrogen and oxygen.

16. The method of claim 13, wherein the nitrogen-oxygen source gas comprises oxygen, and at least one of ammonia and nitrogen.

17. The method of claim 12, wherein the plasma enhanced chemical vapor deposition process is performed in a temperature range substantially between 250 and 400°

C.