PHOTOTRANSISTOR WITH BODY-STRAPPED BASE

• US 20150349186A1
• Filed: 05/30/2014
• Published: 12/03/2015
• Est. Priority Date: 05/30/2014
• Status: Active Grant

• Current Assignee: Klaus Y.J. Hsu, Wispro Technology Consulting Corporation
• Original Assignee: Wispro Technology Consulting Corporation Limited
• Inventors: HSU, KLAUS Y. J., LIAO, BRETT W. C.
• Granted Patent: US 10,553,633 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 27/1463 Pixel isolation structures
• CPC Class Codes: H01L 27/14681 Bipolar transistor imagers
• CPC Class Codes: H01L 27/14683 Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00
• CPC Class Codes: H01L 31/10 characterised by potential barriers, e.g. phototransistors
• CPC Class Codes: H01L 31/11 characterised by two potential barriers, e.g. bipolar phototransistors
• CPC Class Codes: H01L 31/1105 the device being a bipolar phototransistor

Abstract

A photosensing device with a photovoltage sensing mechanism, a graphene layer and a semiconductor layer. The graphene layer is sandwiched between the semiconductor layer and a substrate. The photovoltage sensing mechanism senses the photovoltage created by light impinging on the graphene-semiconductor heterojunction. The strength of the photovoltage is used to indicate the level of illumination of the impinging light.

Claims

1. A photodetector structure characterized in that it incorporates at least one phototransistor wherein a base of the at least one phototransistor is electrically connected to a substrate.

2. The photodetector structure according to claim 1, further comprising an n-type buried layer adjacent to the substrate;

and wherein the substrate is of p-type conductivity and the at least one phototransistor is formed on the buried layer.

3. The photodetector structure according to claim 2, wherein the base is of p-type conductivity and at least one phototransistor comprises:

an n-type epitaxial layer adjacent to the buried layer;

the base is adjacent to the epitaxial layer;

and an n-type emitter layer partially covering the base.

4. The photodetector structure according to claim 1, further comprising an n-type conductivity region adjacent to the substrate;

wherein the substrate is of p-type conductivity; and

the at least one phototransistor are formed on the n-type conductivity region.

5. The photodetector structure according to claim 4, wherein the base is a p-type conductivity region adjacent to the n-type conductivity region.

6. The photodetector structure according to claim 5, wherein a collector region and an emitter region are formed in the p-type conductivity region and separated by an n-channel metal oxide field effect transistor (nMOS FET).

7. The photodetector structure according to claim 1, wherein the electrical connection is made of metallic material or doping connection.

8. The photodetector structure according to claim 1, wherein the at least one phototransistor is a plurality of phototransistors arranged in a one dimensional array.

9. The photodetector structure according to claim 1, wherein the at least one phototransistor is a plurality of phototransistors arranged in a two dimensional array.

10. The photodetector structure according to claim 1, wherein the structure is an electronic module and the at least one phototransistor is a plurality of phototransistors arranged in a matrix and the at least one phototransistor is connected to a multiplexer and a row and column decoder.

11. A method for fabricating a photodetector structure, the photodetector structure comprising at least one phototransistor, wherein the at least one phototransistor is formed by:

providing a p-type substrate;

forming an n-type buried region on the substrate;

forming an n-type epitaxial region on the buried layer;

forming a p-type base on the epitaxial region;

forming an emitter covering a portion of the base; and

electrically connecting the base to the substrate.

12. The method according to claim 11, wherein the electrical connection is made of metallic material or doping connection.

13. The method according to claim 11, wherein the at least one phototransistor is a plurality of phototransistors arranged in a one dimensional array.

14. The method according to claim 11, wherein the at least one phototransistor is a plurality of phototransistors arranged in a two dimensional array.

15. A method for fabricating a photodetector structure, the photodetector structure comprising at least one phototransistor, wherein the at least one phototransistor is formed by:

providing a p-type substrate;

forming an n-type conductivity region on the substrate;

forming a p-type conductivity region on the n-type conductivity region;

doping the p-type conductivity region to form at least one collector and at least one emitters in the p-type conductivity region;

forming an n-channel metal oxide semiconductor field effect transistor (nMOS FET) on the p-type conductivity region; and

electrically connecting the p-type conductivity region to the substrate.

16. The method according to claim 15, wherein the electrical connection is made of metallic material or doping connection.

17. The method according to claim 15, wherein the at least one phototransistor is a plurality of phototransistors arranged in a one dimensional array.

18. The method according to claim 15, wherein the at least one phototransistor is a plurality of phototransistors arranged in a two dimensional array.

19. A photosensitive device, comprising:

a substrate of a first conductivity type;

a buried layer of a second conductivity type adjacent to the substrate; and

at least one phototransistor, comprising;

a base of the first conductivity type;

wherein, the base layer is electrically connected to the substrate.

20. The photosensitive device according to claim 19, wherein the at least one phototransistor is a plurality of phototransistors arranged in a one dimensional array.

21. The photosensitive device according to claim 19, wherein the at least one phototransistor is a plurality of phototransistors arranged in a two dimensional array.

22. The photosensitive device according to claim 19, wherein the electrical connection is made of metallic material or doping connection.

23. A photosensitive device, comprising:

a substrate of a first conductivity type;

an isolation region of a second conductivity type adjacent to the substrate; and

at least one phototransistor, comprising;

a base of the first conductivity type enclosed by the isolation region;

wherein, the base is electrically connected to the substrate.

24. The photosensitive device according to claim 23, wherein the at least one phototransistor is a plurality of phototransistors arranged in a one dimensional array.

25. The photosensitive device according to claim 23, wherein the at least one transistor is a plurality of phototransistors arranged in a two dimensional array.

26. The photosensitive device according to claim 23, wherein the electrical connection is made of metallic material or doping connection.

27. A semiconducting device, comprising:

a substrate; and

a two terminal light sensitive transistor comprising a base;

wherein the base is connected to the substrate.

28. The semiconducting device according to claim 27, wherein the base and the substrate are floating.

29. The semiconducting device according to claim 27, wherein the base is connected to the substrate using metal material or doping connection.

30. The semiconducting device of claim 27, wherein the substrate is of p-type conductivity and the base is of p-type conductivity.

31. The semiconducting device of claim 30, wherein the base is separated from the substrate by an n-type conductivity region.