Optical sensor, method of making the same, and display panel having optical sensor

1. An optical sensor, comprising:

a first electrode;

a second electrode;

a photosensitive silicon-rich dielectric layer disposed between the first electrode and the second electrode; and

a first interfacial silicon-rich dielectric layer disposed between the first electrode and the photosensitive silicon-rich dielectric layer;

wherein a percentage of hydrogen of the first interfacial silicon-rich dielectric layer is higher than a percentage of hydrogen of the photosensitive silicon-rich dielectric layer, and an impedance R 2 of the first interfacial silicon-rich dielectric layer is substantially larger than an impedance R 1 of the photosensitive silicon-rich dielectric layer.

2. The optical sensor of claim 1 , wherein a molecular formula of the photosensitive silicon-rich dielectric layer is SiH W1 O X1 N Y1 , and substantially 1.05<w 1 <1.41, 0.39<x 1 <0.47, and 0≦y 1 ≦1.33.

3. The optical sensor of claim 1 , wherein a molecular formula of the first interfacial silicon-rich dielectric layer is SiH W2 O X2 N Y2 , and w 2 is substantially in the range of 1.15<w 2 <2.27, x 2 is substantially in the range of 0.29<x 2 <1.67, and y 2 is substantially in the range of 0≦y 2 ≦1.33 respectively.

4. The optical sensor of claim 1 , wherein the first electrode is a non-transparent electrode, and the second electrode is a transparent electrode.

5. The optical sensor of claim 1 , wherein the impedance R 1 of the photosensitive silicon-rich dielectric layer is substantially in the range of 5E14<R 1 <5E17, and the impedance R 2 of the first interfacial silicon-rich dielectric layer is substantially in the range of 5E17<R 2 <5E19.

6. The optical sensor of claim 1 , wherein a refractive index n 1 of the photosensitive silicon-rich dielectric layer is substantially in the range of 2.7<n 1 <3.4, and a refractive index n 2 of the first interfacial silicon-rich dielectric layer is substantially in the range of 2.2<n 2 <2.7.

7. The optical sensor of claim 1 , wherein a thickness of the photosensitive silicon-rich dielectric layer is larger than a thickness of the first interfacial silicon-rich dielectric layer.

8. The optical sensor of claim 7 , wherein the thickness of the photosensitive silicon-rich dielectric layer is substantially between 500 angstroms and 4000 angstroms, and the thickness of the first interfacial silicon-rich dielectric layer is substantially between 5 angstroms and 500 angstroms.

9. The optical sensor of claim 1 , further comprising a second interfacial silicon-rich dielectric layer disposed between the photosensitive silicon-rich dielectric layer and the second electrode.

10. The optical sensor of claim 9 , wherein a molecular formula of the second interfacial silicon-rich dielectric layer is SiH W3 O X3 N Y3 , and w 3 is substantially in the range of 1.15<w 3 <2.27, x 3 is substantially in the range of 0.29<x 3 <1.67, and y 3 is substantially in the range of 0≦y 3 ≦1.33 respectively.

11. The optical sensor of claim 9 , wherein a thickness of the photosensitive silicon-rich dielectric layer is larger than a thickness of the second interfacial silicon-rich dielectric layer, the thickness of the photosensitive silicon-rich dielectric layer is substantially between 500 angstroms and 4000 angstroms, and the thickness of the second interfacial silicon-rich dielectric layer is substantially between 5 angstroms and 500 angstroms.

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

providing a first electrode;

forming a first interfacial silicon-rich dielectric layer on the first electrode;

forming a photosensitive silicon-rich dielectric layer on the first interfacial silicon-rich dielectric layer; and

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

wherein a percentage of hydrogen of the first interfacial silicon-rich dielectric layer is higher than a percentage of hydrogen of the photosensitive silicon-rich dielectric layer, and an impedance R 2 of the first interfacial silicon-rich dielectric layer is substantially larger than an impedance R 1 of the photosensitive silicon-rich dielectric layer.

13. The method of forming an optical sensor of claim 12 , wherein forming the first interfacial silicon-rich dielectric layer comprises steps of performing a plasma-enhanced chemical vapor deposition (PECVD) process, and introducing silane (SiH 4 ) and nitrous oxide (N 2 O) during the PECVD process.

14. The method of forming an optical sensor of claim 13 , wherein a gas flow rate ratio of SiH 4 /N 2 O for the PECVD process is 1.8.

15. The method of forming an optical sensor of claim 12 , wherein forming the photosensitive silicon-rich dielectric layer comprises steps of performing a PECVD process, and introducing SiH 4 , N 2 O and hydrogen during the PECVD process.

16. The method of forming an optical sensor of claim 15 , wherein a gas flow-rate ratio of SiH 4 /N 2 O for the PECVDE process is 1.8, and a flow rate of hydrogen is substantially 4500 sccm.

17. The method of forming an optical sensor of claim 12 , wherein a molecular formula of the first interfacial silicon-rich dielectric layer is SiH W2 O X2 N Y2 , and w 2 is substantially in the range of 1.15<w 2 <2.27, x 2 is substantially in the range of 0.29<x 2 <1.67, and y 2 is substantially in the range of 0≦y 2 ≦1.33 respectively.

18. The method of forming an optical sensor of claim 12 , wherein a molecular formula of the photosensitive silicon-rich dielectric layer is SiH W1 O X1 N Y1 , and w 1 is substantially in the range of 1.05<w 1 <1.41, x 1 is substantially in the range of 0.39<x 1 <0.47, and y 1 is substantially in the range of 0≦y 1 ≦1.33 respectively.

19. The method of forming an optical sensor of claim 12 , wherein the impedance R 1 of the photosensitive silicon-rich dielectric layer is substantially in the range of 5E14<R 1 <5E17, and the impedance R 2 of the first interfacial silicon-rich dielectric layer is substantially in the range of 5E17<R 2 <5E19.

20. The method of forming an optical sensor of claim 12 , further comprising forming a second interfacial silicon-rich dielectric layer on the photosensitive silicon-rich dielectric layer firstly before forming the second electrode.

21. The method of forming an optical sensor of claim 20 , wherein a molecular formula of the second interfacial silicon-rich dielectric layer is SiH W3 O X3 N Y3 , and w 3 is substantially in the range of 1.15<w 3 <2.27, x 3 is substantially in the range of 0.29<x 3 <1.67, and y 3 is substantially in the range of 0≦y 3 ≦1.33 respectively.

22. The method of forming an optical sensor of claim 20 , wherein forming the second interfacial silicon-rich dielectric layer comprises steps of performing a PECVD process, and introducing SiH 4 and N 2 O during the PECVD process.

23. The method of forming an optical sensor of claim 22 , wherein a gas flow rate ratio of SiH 4 /N 2 O for the PECVD process is 1.8.

24. A display panel, comprising:

a substrate having at least a thin film transistor region and at least an optical sensor region defined thereon;

a thin film transistor disposed in the thin film transistor region; and

an optical sensor disposed in the optical sensor region, wherein the optical sensor comprises:

a first electrode disposed on the substrate;

a second electrode;

a photosensitive silicon-rich dielectric layer disposed between the first electrode and the second electrode; and

a first interfacial silicon-rich dielectric layer disposed between the first electrode and the photosensitive silicon-rich dielectric layer;

wherein a percentage of hydrogen of the first interfacial silicon-rich dielectric layer is higher than a percentage of hydrogen of the photosensitive silicon-rich dielectric layer, and an impedance R 2 of the first interfacial silicon-rich dielectric layer is substantially larger than an impedance R 1 of the photosensitive silicon-rich dielectric layer.

25. The display panel of claim 24 , further comprising a second interfacial silicon-rich dielectric layer disposed between the photosensitive silicon-rich dielectric layer and the second electrode.

26. The display panel of claim 24 , wherein the thin film transistor comprises a gate electrode, and the first electrode of the optical sensor and the gate electrode of the thin film transistor are in a same metal pattern layer.

27. The display panel of claim 24 , wherein the thin film transistor comprises a source/drain electrode, and the first electrode of the optical sensor and the source/drain electrode of the thin film transistor are in a same metal pattern layer.

28. The display panel of claim 24 , further comprising a pixel electrode, and the pixel electrode and the second electrode of the optical sensor are in a same transparent conductive pattern layer.