Tetra-lateral position sensing detector

• US 9,577,121 B2
• Filed: 08/21/2015
• Issued: 02/21/2017
• Est. Priority Date: 05/12/2009
• Status: Active Grant

• Current Assignee: OSI Optoelectronics, Inc. (OSI Systems Incorporated)
• Original Assignee: OSI Optoelectronics, Inc. (OSI Systems Incorporated)
• Inventors: Bui, Peter Steven, Taneja, Narayan Dass
• Primary Examiner(s): Tran, Thanh Y
• Application Number:
  US14/832,079
• Publication Number:
  US 20160056310A1
• Time in Patent Office: 550 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 31/02024 Position sensitive and lateral effect photodetectors; Quadrant photodiodes
• CPC Class Codes: H01L 31/022408 for devices characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/022416 comprising ring electrodes
• CPC Class Codes: H01L 31/03042 characterised by the doping material
• CPC Class Codes: H01L 31/03046 including ternary or quaternary compounds, e.g. GaAlAs, InGaAs, InGaAsP
• CPC Class Codes: H01L 31/109 the potential barrier being of the PN heterojunction type
• CPC Class Codes: H01L 31/11 characterised by two potential barriers, e.g. bipolar phototransistors
• CPC Class Codes: H01L 31/184 the active layers comprising only AIIIBV compounds, e.g. GaAs, InP
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

The present invention is directed to a position sensing detector made of a photodiode having a semi insulating substrate layer; a buffered layer that is formed directly atop the semi-insulating substrate layer, an absorption layer that is formed directly atop the buffered layer substrate layer, a cap layer that is formed directly atop the absorption layer, a plurality of cathode electrodes electrically coupled to the buffered layer or directly to the cap layer, and at least one anode electrode electrically coupled to a p-type region in the cap layer. The position sensing detector has a photo-response non-uniformity of less than 2% and a position detection error of less than 10 μm across the active area.

Claims

1. A position sensing detector comprising a photodiode having an active area, said photodiode comprising

a semi insulating substrate layer;

a buffered layer, wherein said buffered layer is formed directly atop the semi-insulating substrate layer;

an absorption layer, wherein said absorption layer is formed directly atop the buffered layer;

a cap layer, wherein said cap layer is formed directly atop the absorption layer;

four cathode electrodes electrically coupled to said buffered layer, wherein each of said four cathode electrodes is positioned parallel to other of said four cathode electrodes and in opposing corners of the photodiode; and

at least one anode electrode electrically coupled to a p-type region in said cap layer, wherein said detector is capable of detecting eye-safe wavelengths, wherein a shunt resistance of the position sensing detector at −

10 mV ranges from 1 Megaohms to 8 Megaohms and wherein a capacitance of the position sensing detector at 0 V ranges from 322 picofarads to 900 picofarads.

2. The position sensing detector of claim 1 wherein said buffered layer comprises InP and wherein said eye-safe wavelengths are from 1.3-1.55 μ

m.

3. The position sensing detector of claim 1 wherein said absorption layer comprises InGaAs.

4. The position sensing detector of claim 1 wherein said cap layer comprises InP.

5. The position sensing detector of claim 1 wherein a photo response non-uniformity of said position sensing detector is less than 1 micron across said active area.

6. The position sensing detector of claim 1 wherein a position detection error of said position sensing detector, in both the X and Y direction, is on the order of 100 μ

m across the active area.

7. The position sensing detector of claim 1 wherein the photodiode further comprises an anti-reflective layer positioned atop the cap layer.

8. The position sensing detector of claim 1 wherein said p-type region in said cap layer is formed by diffusing a region of said cap layer with a suitable dopant to create said p-type region.

9. The position sensing detector of claim 8 wherein said dopant is zinc.

10. A position sensing detector comprising a photodiode having an active area, said photodiode comprising

a semi insulating substrate layer;

a buffered layer, wherein said buffered layer is formed directly atop the semi-insulating substrate layer;

an absorption layer, wherein said absorption layer is formed directly atop the buffered layer;

a cap layer, wherein said cap layer is formed directly atop the absorption layer, wherein a p-n junction is formed between said cap layer and said absorption layer;

four cathode electrodes electrically coupled to said buffered layer, wherein each of said four cathode electrodes is positioned parallel to other of said four cathode electrodes and in opposing corners of the photodiode; and

at least one anode electrode electrically coupled to said cap layer, wherein a shunt resistance of the position sensing detector at −

10 mV ranges from 1 Megaohms to 8 Megaohms and wherein a capacitance of the position sensing detector at −

5 V ranges from 176 picofarads to 375 picofarads.

11. The position sensing detector of claim 10 wherein said buffered layer comprises at least one of InGaAs or InP.

12. The position sensing detector of claim 10 wherein said absorption layer comprises at least one of InGaAs or InP.

13. The position sensing detector of claim 10 wherein said cap layer comprises at least one of InGaAs or InP.

14. The position sensing detector of claim 10 wherein the position detection error, in both the X and Y direction is on the order of 100 μ

m across the active area.

15. The position sensing detector of claim 10 wherein said p-n junction is formed by diffusing a region of said cap layer with a suitable dopant.

16. The position sensing detector of claim 10 wherein said p-n junction is formed by diffusing a region of said absorption layer with a suitable dopant.

17. A position sensing detector comprising a photodiode having an active area, said photodiode comprising

a semi insulating substrate layer;

a buffered layer, wherein said buffered layer is formed directly atop the semi-insulating substrate layer;

an absorption layer, wherein said absorption layer is formed directly atop the buffered layer substrate layer;

a cap layer, wherein said cap layer is formed directly atop the absorption layer, wherein a p-n junction is formed between said cap layer and said absorption layer;

four cathode electrodes electrically coupled to said cap layer, wherein each of said four cathode electrodes is positioned parallel to other of said four cathode electrodes and in opposing corners of the photodiode; and

at least one anode electrode electrically coupled to said cap layer, wherein a shunt resistance of the position sensing detector at −

10 mV ranges from 1 Megaohms to 8 Megaohms, wherein a capacitance of the position sensing detector at 0 V ranges from 322 picofarads to 900 picofarads, and wherein a capacitance of the position sensing detector at −

5 V ranges from 176 picofarads to 375 picofarads.