Semiconductor photodetector device

• US 5,040,039 A
• Filed: 08/07/1990
• Issued: 08/13/1991
• Est. Priority Date: 01/25/1990
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hattori, Ryo, Hironaka, Misao
• Primary Examiner(s): Jackson, Jr., Jerome
• Application Number:
  US07/563,411
• Time in Patent Office: 371 Days
• Field of Search: 357/30, 357/65
• US Class Current: 257/463
• CPC Class Codes: H01L 31/02161 for devices characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/02164 for shielding light, e.g. light blocking layers, cold shields for infrared detectors
• CPC Class Codes: H01L 31/022416 comprising ring electrodes
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type

Abstract

A photodetector device includes a stack of a light-absorbing layer, a window layer on a substrate, and a region in the window layer formed by reversing the conductivity type of the window layer extending to the light-absorbing layer. A surface protecting film is disposed on the window layer, with a light receiving area being left uncovered. An electrode makes ohmic contact with the reversed conductivity region and surrounds the light receiving area. A metallic light-blocking film is disposed on the protecting film with an insulating gap therebetween. The inner edge of the light-absorbing film is located in alignment with or inward of the p-n junction between the reversed conductivity type region and the window layer.

Claims

1. A semiconductor photodetector device comprising:

a substrate of a first conductivity type;

a light-absorbing layer of the first conductivity type disposed on said substrate;

a window layer of the first conductivity type disposed on said light-absorbing layer opposite said substrate;

a region of a second conductivity type opposite the first conductivity type disposed in a portion of said window layer extending to said light-absorbing layer and forming a conductivity type junction with said window layer;

a surface-protecting film disposed directly on and contacting said window layer including an aperture leaving a portion of said second conductivity type region exposed as a light-receiving area;

a first electrode disposed on said surface-protecting film surrounding said light-receiving area and in ohmic contact with said second conductivity type region;

a metallic light-blocking film disposed directly on and contacting said surface-protecting film surrounding said first electrode with a gap therebetween electrically insulating said metallic light-blocking film from said first electrode, said metallic light-blocking film having an inner edge at the gap opposite said first electrode; and

a second electrode disposed on said substrate opposite said light-absorbing layer in ohmic contact therewith wherein the inner edge or said metallic light-blocking film is located no farther outward from said light-receiving area than the conductivity type junction between said second conductivity type region and said window layer.

2. A semiconductor photodetector device according to claim 1 wherein the inner edge of said metallic light-blocking film is aligned with the conductivity type junction between second conductivity type region and said window layer.

3. A semiconductor photodetector device according to claim 1 wherein the inner edge of said metallic light-blocking film is located inward, relative to said light-receiving area, of the conductivity type junction between said second conductivity type region and said window layer.

4. A semiconductor photodetector device according to claim 1 including an anti-reflection film disposed on said light-receiving area.

5. A semiconductor photodetector device according to claim 3 including an anti-reflection film disposed on said light-receiving area.

6. A semiconductor photodetector device according to claim 1 including an anti-reflection film disposed on said light-receiving area.

7. A semiconductor photodetector device according to claim 1 including a buffer layer of the first conductivity type interposed between said light-absorbing layer and said substrate.

8. A semiconductor photodetector device according to claim 7 wherein the inner edge of said metallic light-blocking film is aligned with the conductivity type junction between said second conductivity type region and said window layer.

9. A semiconductor photodetector device according to claim 7 wherein the inner edge of said metallic light-blocking film is located inward, relative to said light-receiving area, of the conductivity type junction between said second conductivity type region and said window layer.

10. A semiconductor photodetector device according to claim 7 wherein an anti-reflection film disposed on said light-receiving area.

11. A semiconductor photodetector device according to claim 8 wherein an anti-reflection film disposed said light-receiving area.

12. A semiconductor photodetector device according to claim 9 wherein an anti-reflection film disposed said light-receiving area.