Semiconductor photodetector device with short lifetime region

• US 5,272,364 A
• Filed: 06/24/1992
• Issued: 12/21/1993
• Est. Priority Date: 07/01/1991
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hironaka, Misao
• Primary Examiner(s): MINTEL, WILLIAM A
• Application Number:
  US07/906,222
• Time in Patent Office: 545 Days
• Field of Search: 257/186, 257/187, 257/184, 257/185, 257/438, 257/439
• US Class Current: 257/185
• CPC Class Codes: H01L 31/02161 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 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 31/1075 in which the active layers, e.g. absorption or multiplication layers, form an heterostructure, e.g. SAM structure

Abstract

A semiconductor photodetector device includes a second conductivity type region extending through a first conductivity type window layer to a first conductivity type light absorbing layer and a short carrier lifetime region surrounding ht second conductivity type region such that the lifetime of minority carriers generated in the light absorbing layer outside a depletion layer located around the second conductivity type region is significantly shorter than the lifetime of minority carriers elsewhere within the light absorbing layer. The photodetector device can respond quickly to variations in incident light because the collection of charge carriers generated in the light absorbing layer outside the depletion layer is reduced.

Claims

1. A semiconductor photodetector device comprising:

a semiconductor substrate of a first conductivity type;

a light absorbing layer of the first conductivity type having a bandgap and disposed on said substrate for generating minority and majority charge carriers in response to incident light, the charge carriers having lifetimes in said light absorbing layer before recombination;

a window layer of the first conductivity type having a light incident surface and disposed on said light absorbing layer, said window layer having a bandgap wider than the bandgap of said light absorbing layer;

a second conductivity type region of an opposite conductivity type from the first conductivity type extending from the light incident surface of said window layer into said window layer and at least proximate said light absorbing layer so that a depletion layer adjacent said second conductivity type region is contained with in said light absorbing layer and said window layer;

a surface protecting film substantially transparent to incident light disposed on part of said second conductivity type region at the light incident surface of said window layer and on part of the light incident surface of said window layer;

a short lifetime region of the first conductivity type disposed within said light absorbing layer circumferentially surrounding said second conductivity type region, the lifetime of the minority carries within said short lifetime region being less than one hundredth the lifetime of the minority carriers within said light absorbing layer outside said short lifetime region;

a first electrode disposed on said surface protecting film in electrical contact with said second conductivity type region; and

a second electrode disposed on and in electrical contact with said semiconductor substrate.

3. The semiconductor photodetector device according to claim 1 wherein said first conductivity type is n-type and said second conductivity type is p-type, said second conductivity type region contains a p-type impurity, such as Zn, diffused from the light incident surface of said window layer, and said short lifetime region contains an n-type impurity, such as at least one of Si, Te S, Se, and Sn, diffused or implanted from the surface of said window layer.

5. The semiconductor photodetector device according to claim 1 wherein said short lifetime region contains implanted protons.

7. The semiconductor photodetector device according to claim 1 wherein said second conductivity type region extends through said window layer and into said light absorbing layer.

9. The semiconductor photodetector device according to claim 1 wherein said short lifetime region extends through said window layer and into said light absorbing layer.

10. The semiconductor photodetector device according to claim 9 wherein said short lifetime region extends through said light absorbing layer.

13. The semiconductor photodetector device according to claim 1 including a first conductivity type buffer layer interposed between and contacting said substrate and said light absorbing layer.

2. A semiconductor photodetector device comprising:

an InP substrate of a first conductivity type;

an InGaAs light absorbing layer of the first conductivity type having a bandgap and disposed on said InP substrate for generating minority and majority charge carriers in response to incident light, the charge carriers having lifetimes in said light absorbing layer before recombination;

an InP window layer of the first conductivity type having a light incident surface and disposed on said light absorbing layer, said InP window layer having a bandgap wider than the bandgap of said InGaAs light absorbing layer;

a second conductivity type region of an opposite conductivity type form the first conductivity type extending from the light incident surface of said InP window layer into said InP window layer and at least proximate said light absorbing layer so that a depletion layer adjacent said second conductivity type region is contained within said light absorbing layer and said window layer;

a surface protecting film substantially transparent to incident light disposed on part of said second conductivity type region at the light incident surface of said window layer and on part of the light incident surface of said window layer;

a short lifetime region of the first conductivity type disposed within said light absorbing layer circumferentially surrounding said second conductivity type region, the lifetime of the minority carriers within said short lifetime region being less than one-hundredth the lifetime of the minority carriers within said light absorbing layer outside said short lifetime region;

a first electrode disposed on said surface protecting film in electrical contact with said second conductivity type region; and

a second electrode disposed on and in electrical contact with said semiconductor substrate.

4. The semiconductor photodetector device according to claim 2 wherein said first conductivity type is n-type and said second conductivity type is p-type, said second conductivity type region contains a p-type impurity, such as Zn, diffused form the light incident surface of said window layer, and said short lifetime region contains an n-type impurity, such as at least one of Si, Te, S, Se, and Sn, diffused or implanted from the surface of said window layer.

6. The semiconductor photodetector device according to claim 2 wherein said short lifetime region contains implanted protons.

8. The semiconductor photodetector device according to claim 2 wherein said second conductivity type region extends through said window layer and into said light absorbing layer.

11. The semiconductor photodetector device according to claim 2 wherein said short lifetime region extends through said window layer and into said light absorbing layer.

12. The semiconductor photodetector device according to claim 11 wherein said short lifetime region extends through said light absorbing layer.

14. The semiconductor photodetector device according to claim 2 including a first conductivity type buffer layer interposed between and contacting said substrate and said light absorbing layer.