PHOTONIC LOCK BASED HIGH BANDWIDTH PHOTODETECTOR

• US 20140284450A1
• Filed: 06/06/2014
• Published: 09/25/2014
• Est. Priority Date: 11/27/2012
• Status: Active Grant

• Current Assignee: Forelux, Inc.
• Original Assignee: Forelux, Inc.
• Inventors: Chen, Shu-Lu, Na, Yun-Chung
• Granted Patent: US 9,362,428 B2
• Time in Patent Office: Days
• US Class Current: 250/205
• CPC Class Codes: H01L 27/14629 Reflectors
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 31/0232 Optical elements or arrangements associated with the device H01L31/0236 takes precedence; for photovoltaic cells H01L31/054; for photovoltaic modules H02S40/20
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• CPC Class Codes: H01L 31/102 characterised by only one potential barrier
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof

Abstract

The technique introduced herein decouples the traditional relationship between bandwidth and responsivity, thereby providing a more flexible and wider photodetector design space. In certain embodiments of the technique introduced here, a photodetector device includes a first mirror, a second mirror, and a light absorption region positioned between the first and second reflective mirrors. For example, the first mirror can be a partial mirror, and the second mirror can be a high-reflectivity mirror. The light absorption region is positioned to absorb incident light that is passed through the first mirror and reflected between the first and second mirrors. The first mirror can be configured to exhibit a reflectivity that causes an amount of light energy that escapes from the first mirror, after the light being reflected back by the second mirror, to be zero or near zero.

Claims

1. A photodetector device comprising:

a first reflective region;

a second reflective region; and

a light absorption region positioned between the first and second reflective regions so as to absorb light passed through the first reflective region and reflected between the first and second reflective regions,

wherein the first reflective region has a reflectivity that causes an amount of light energy that escapes from the first reflective region, after the light being reflected by the second reflective region, to be substantially zero.

2. The device of claim 1, wherein (a) the first reflective region'"'"'s reflectivity, (b) a reflectivity of the second reflection region, and (c) an attenuation coefficient of the light absorption region are collectively configured such that, when the light enters the light absorption region and reflects between the first and second reflective regions, the light resonates in the light absorption region.

3. The device of claim 1, wherein the first reflective region'"'"'s reflectivity is configured to be substantially equal to a one-circulation attenuation coefficient of the light absorption region.

4. The device of claim 3, wherein the one-circulation attenuation coefficient indicates a ratio of remainder light energy over entrance light energy in one circulation.

5. The device of claim 1, wherein the first reflective region'"'"'s reflectivity is less than a reflectivity of the second reflective region.

6. The device of claim 1, further comprising:

a waveguide configured to pass the light through the first reflective region into the light absorption region.

7. The device of claim 1, wherein the light absorption region comprises a light absorption material that is disposed on substantially the same planar surface as the first and second reflective regions.

8. The device of claim 1, wherein the light absorption region comprises (a) a cavity layer disposed on substantially the same planar surface as the first and second reflective regions, and (b) a light absorption layer that is disposed over the cavity layer,

wherein the light absorption layer and the cavity layer are of different materials.

9. The device of claim 1, wherein the first reflective region is disposed over the light absorption region, and wherein the light absorption region is disposed over the second reflective region.

10. The device of claim 1, wherein the light absorption region comprises a photodiode or an avalanche photodiode layered structure.

11. The device of claim 1, wherein the first and second reflective regions are selected from a group including:

a distributed Bragg reflector (DBR), a metallic reflector, a corner mirror, and a reflection trench.

12. The device of claim 1, wherein the light absorption region comprises a Group III-V compound, germanium, or a combination thereof.

13. A method for forming a photodetector device, the method comprising:

forming a light absorption region and first reflective region and a second reflective region over a substrate, wherein the first and second reflective regions are formed on substantially the same planar surface; and

forming a light absorption region between the first and second reflective regions so as to absorb light passed through the first reflective region and reflected between the first and second reflective regions,

wherein the first reflective region has a reflectivity that causes an amount of light energy that escapes from the first reflective region, after the light being reflected by the second reflective region, to be substantially zero.

14. The method of claim 13, wherein (a) the first reflective region'"'"'s reflectivity, (b) a reflectivity of the second reflection region, and (c) an attenuation coefficient of the light absorption region are collectively configured such that, when the light enters the light absorption region and reflects between the first and second reflective regions, the light resonates in the light absorption region.

15. The method of claim 13, wherein the first reflective region'"'"'s reflectivity is configured to be substantially equal to a one-circulation attenuation coefficient of the light absorption region.

16. The method of claim 13, wherein the first reflective region'"'"'s reflectivity is less than a reflectivity of the second reflective region.

17. The method of claim 13, further comprising:

forming a waveguide over the substrate, wherein the waveguide is configured to pass the light through the first reflective region into the light absorption region.

18. The method of claim 13, wherein forming the light absorption region comprises:

disposing a light absorption material on substantially the same planar surface as the first and second reflective regions.

19. The method of claim 13, wherein forming the light absorption region comprises:

during the step of forming the first and the second reflective regions, disposing a cavity layer on substantially the same planar surface as the first and second reflective regions; and

disposing a light absorption layer over the cavity layer, wherein the light absorption layer and the cavity layer are of different materials.

20. A method for forming a photodetector device, the method comprising:

forming a light absorption region; and

forming a first and a second reflective regions;

wherein the light absorption region is positioned between the first and second reflective regions so as to absorb light passed through the first reflective region and reflected between the first and second reflective regions, and

wherein the first reflective region has a reflectivity that causes an amount of light energy that escapes from the first reflective region, after the light being reflected by the second reflective region, to be substantially zero.

21. The method of claim 20, wherein (a) the first reflective region'"'"'s reflectivity, (b) a reflectivity of the second reflection region, and (c) an attenuation coefficient of the light absorption region are collectively configured such that, when the light enters the light absorption region and reflects between the first and second reflective regions, the light resonates in the light absorption region.

22. The method of claim 20, wherein the first reflective region'"'"'s reflectivity is configured to be substantially equal to a one-circulation attenuation coefficient of the light absorption region.

23. The method of claim 20, wherein the first reflective region'"'"'s reflectivity is less than a reflectivity of the second reflective region.

24. An optoelectronic system for sensing optical signals, the system comprising:

a microcontroller;

a memory; and

an optoelectronic apparatus including a photodetector that includes;

a first reflective region;

a second reflective region; and

a light absorption region positioned between the first and second reflective regions so as to absorb light passed through the first reflective region and reflected between the first and second reflective regions,

wherein the first reflective region has a reflectivity that causes an amount of light energy that escapes from the first reflective region, after the light being reflected by the second reflective region, to be substantially zero,

wherein (a) the first reflective region'"'"'s reflectivity, (b) a reflectivity of the second reflection region, and (c) an attenuation coefficient of the light absorption region are collectively configured such that, when the light enters the light absorption region and reflects between the first and second reflective regions, the light resonates in the light absorption region,

wherein the first reflective region'"'"'s reflectivity is configured to be substantially equal to a one-circulation attenuation coefficient of the light absorption region, and

wherein the one-circulation attenuation coefficient indicates a ratio of remainder light energy over entrance light energy in one circulation.