Very high speed photodetector system using a PIN photodiode array for position sensing

• US 6,831,263 B2
• Filed: 06/04/2002
• Issued: 12/14/2004
• Est. Priority Date: 06/04/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Skurnik, David, Sprague, Randall Brian, Jones, Geoffrey Hugh, Law, Waisiu, Abbott, Eric Charles
• Primary Examiner(s): Allen, Stephone B.
• Assistant Examiner(s): Lee, Patrick J.
• Application Number:
  US10/163,204
• Publication Number:
  US 20030222200A1
• Time in Patent Office: 924 Days
• Field of Search: 250/208.2, 250/206.1, 250/214.R, 327/514, 356/213, 356/218, 257/443, 257/458
• US Class Current: 250/208.2
• CPC Class Codes: H01L 21/823807 with a particular manufacturing method of the channel structures, e.g. channel implants, halo or pocket implants, or channel materials
• CPC Class Codes: H01L 21/823878 isolation region manufacturing related aspects, e.g. to avoid interaction of isolation region with adjacent structure
• CPC Class Codes: H01L 27/0922 Combination of complementary transistors having a different structure, e.g. stacked CMOS, high-voltage and low-voltage CMOS
• CPC Class Codes: H01L 27/1446 in a repetitive configuration
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/7843 the means being an applied insulating layer
• CPC Class Codes: H01L 29/7846 the means being located in the lateral device isolation region, e.g. STI

Abstract

An apparatus for detecting a centroid of a spot produced by electromagnetic radiation, e.g., optic radiation, using an array of PIN photodiodes serving as photodetectors and being organized in columns and in rows. Vertical connections are used to interconnect the PIN photodiodes in the columns in accordance with a first pattern that interconnects two or more adjacent columns. Horizontal connections are used to interconnect PIN photodiodes in the rows in accordance with a second pattern that interconnects two or more adjacent rows. The first and second patterns of interconnections can include just two adjacent columns and two adjacent rows, respectively and form a checkerboard interconnect pattern. The interconnections are made such that there are no anode connections between the PIN photodiodes in the rows and columns. The apparatus has a processing circuitry for rapidly deriving an X-extent of the centroid from current signals obtained from the columns and a Y-extent of the centroid from current signals obtained from the rows.

Claims

1. An apparatus for detecting a centroid of a spot produced by electromagnetic radiation, said apparatus comprising:

a) an array of PIN photodiodes organized in columns and in rows;

b) vertical connections for interconnecting said PIN photodiodes in said columns in a first pattern interconnecting at least two adjacent columns;

c) horizontal connections for interconnecting said PIN photodiodes in said rows in a second pattern to interconnecting at least two adjacent rows, whereby no anode connection exists between said rows and said columns;

d) processing means for deriving an X-extent of said centroid from said columns and a Y-extent of said centroid from said rows.

2. The apparatus of claim 1, wherein said first pattern and said second pattern yield a checkerboard interconnection pattern.

3. The apparatus of claim 2, wherein said processing means comprises a multiplexing circuit for multiplexing a predetermined number of said columns and of said rows.

4. The apparatus of claim 3, wherein said processing means further comprises a discrimination circuit for selecting said predetermined number of said columns and of said rows according to illumination level.

5. The apparatus of claim 3, further comprising a logic for initially measuring said X-extent and said Y-extent from all of said columns and said rows, and for subsequently determining an X-coordinate and a Y-coordinate of said centroid from said predetermined number of said columns and said rows.

6. The apparatus of claim 2, wherein said processing means further comprises a calibration means for adjusting at least one detection characteristic of said PIN photodiodes.

7. The apparatus of claim 2, wherein said processing means further comprises a filtering means.

8. The apparatus of claim 7, wherein said filtering means is selected from the group consisting of time-domain cross-talk filters and weighted average noise compression filters.

9. The apparatus of claim 2, wherein said processing means further comprises a self-test circuit.

10. The apparatus of claim 2, wherein said PIN photodiodes share a common cathode.

11. The apparatus of claim 10, wherein said common cathode is provided on a backside of said apparatus facing said electromagnetic radiation.

12. The apparatus of claim 11, wherein anode connections are made on a front side of said apparatus opposite said backside.

13. The apparatus of claim 12, further comprising a top cathode on said front side.

14. The apparatus of claim 13, wherein said top cathode comprises cathode rings.

15. A method for detecting a centroid of a spot produced by electromagnetic radiation, said method comprising:

a) providing an array of PIN photodiodes organized in columns and in rows;

b) interconnecting said PIN photodiodes in said columns in a first pattern interconnecting at least two adjacent columns;

c) interconnecting said PIN photodiodes in said rows in a second pattern interconnecting at least two adjacent rows, such that no anode connection exists between said rows and said columns; and

d) deriving an X-extent of said centroid from said columns and a Y-extent of said centroid from said rows.

16. The method of claim 15, wherein said first pattern and said second pattern yield a checkerboard interconnection pattern.

17. The method of claim 16, wherein said deriving comprises a first measurement of said X-extent at and said Y-extent from all of said columns and all of said rows.

18. The method of claim 17, wherein said deriving further comprises multiplexing a predetermined number of said columns and said rows and a deriving an X-coordinate and a Y-coordinate of said centroid from said predetermined number of said columns and said rows.