Light-emitting semiconductor device with reduced nonradiative recombination

• US 6,313,483 B1
• Filed: 05/17/1999
• Issued: 11/06/2001
• Est. Priority Date: 07/01/1998
• Status: Active Grant

• Current Assignee: Oki Data Corporation (OKI Electric Industry Company Limited)
• Original Assignee: OKI Data Communication
• Inventors: Ogihara, Mitsuhiko, Hamano, Hiroshi, Taninaka, Masumi
• Primary Examiner(s): Lee, Eddie
• Assistant Examiner(s): Lee, Eugene
• Application Number:
  US09/312,848
• Time in Patent Office: 904 Days
• Field of Search: 257/95, 257/79, 257/81, 257/82, 257/83, 257/84, 257/102, 257/184, 372/45
• US Class Current: 257/79
• CPC Class Codes: B41J 2/45 using light-emitting diode [LED] or laser arrays
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/40 Materials therefor

Abstract

A light-emitting semiconductor device has a semi-insulating semiconductor surface layer overlying a conductive semiconductor layer of a first conductive type. A diffusion region of a second conductive type extends through the semi-insulating semiconductor surface layer and ends in the conductive semiconductor layer. Positive and negative electrode contacts are provided on the upper surface of the device. Nonradiative recombination near the surface of the device is reduced because there is no pn junction in the semi-insulating semiconductor surface layer, and the device structure is suitable for matrix driving.

Claims

1. A light-emitting semiconductor device, comprising:

a conductive semiconductor layer of a first conductive type;

a semi-insulating semiconductor surface layer formed on said conductive semiconductor layer;

a first diffusion region, of a second conductive type opposite to said first conductive type, extending through said semi-insulating semiconductor surface layer into said conductive semiconductor layer, having a depthwise diffusion front ending in said conductive semiconductor layer;

a second diffusion region of said first conductive type, extending through said semi-insulating semiconductor surface layer at least to an interface between said semi-insulating semiconductor surface layer and said conductive semiconductor layer;

a first electrode forming an ohmic contact with said first diffusion region; and

a second electrode forming an ohmic contact with said second diffusion region.

2. The light-emitting semiconductor device of claim 1, wherein:

said semi-insulating semiconductor surface layer comprises gallium arsenide;

said conductive semiconductor layer comprises aluminum gallium arsenide; and

said first diffusion region comprises a zinc impurity.

3. The light-emitting semiconductor device of claim 1, wherein said conductive semiconductor layer further comprises:

a light-emitting layer including the depthwise diffusion front of said first diffusion region; and

a cladding layer disposed between said light-emitting layer and said semi-insulating semiconductor surface layer.

4. The light-emitting semiconductor device of claim 3, wherein:

said light-emitting layer comprises aluminum gallium arsenide;

said cladding layer comprises aluminum gallium arsenide with a higher concentration of aluminum than in said light-emitting layer; and

said first diffusion region comprises a zinc impurity.

5. The light-emitting semiconductor device of claim 1, wherein said conductive semiconductor layer further comprises:

a cladding layer; and

a light-emitting layer disposed between said cladding layer and said semi-insulating semiconductor surface layer, including the depthwise diffusion front of said first diffusion region.

6. The light-emitting semiconductor device of claim 5, wherein:

said light-emitting layer comprises aluminum gallium arsenide;

said cladding layer comprises aluminum gallium arsenide with a higher concentration of aluminum than in said light-emitting layer; and

said first diffusion region comprises a zinc impurity.

7. The light-emitting semiconductor device of claim 1, wherein said conductive semiconductor layer further comprises:

a light-emitting layer including the depthwise diffusion front of said first diffusion region;

a first cladding layer disposed adjacently above said light-emitting layer; and

a second cladding layer disposed adjacently below said light-emitting layer.

8. The light-emitting semiconductor device of claim 7, wherein:

said light-emitting layer comprises aluminum gallium arsenide;

said first cladding layer and said second cladding layer comprise aluminum gallium arsenide with a higher concentration of aluminum than in said light-emitting layer; and

said first diffusion region comprises a zinc impurity.

9. The light-emitting semiconductor device of claim 1, wherein a portion of said semi-insulating semiconductor surface layer, including a lateral diffusion front of said first diffusion region, is removed by etching.

10. The light-emitting semiconductor device of claim 9, wherein a portion of an interface between said conductive semiconductor layer and the removed portion of said semi-insulating semiconductor surface layer is also removed by etching.

11. The light-emitting semiconductor device of claim 1, further comprising a semi-insulating semiconductor substrate layer, said conductive semiconductor layer being disposed between said semi-insulating semiconductor surface layer and said semi-insulating semiconductor substrate layer.

12. A light-emitting semiconductor array device comprising a matrix-driven plurality of light-emitting semiconductor devices as described in claim 11, the light-emitting semiconductor devices sharing said semi-insulating semiconductor substrate layer.

13. A light-emitting semiconductor device having an upper surface, comprising:

a conductive semiconductor layer of a first conductive type;

an etched island formed by etching a semi-insulating semiconductor surface layer formed on said conductive semiconductor layer;

a diffusion region, of a second conductive type opposite to said first conductive type, formed before said semi-insulating semiconductor surface layer is etched, including said etched island, having a depthwise diffusion front ending in said conductive semiconductor layer;

a first electrode disposed on said upper surface, forming an ohmic contact with said etched island; and

a second electrode disposed on said upper surface, forming an ohmic contact with said conductive semiconductor layer outside said diffusion region.

14. The light-emitting semiconductor device of claim 13, wherein said conductive semiconductor layer further comprises:

a light-emitting layer including the depthwise diffusion front of said diffusion region; and

a first cladding layer disposed above said light-emitting layer, said second electrode making ohmic contact with said first cladding layer.

15. The light-emitting semiconductor device of claim 14, wherein:

said light-emitting layer comprises aluminum gallium arsenide;

said first cladding layer comprises aluminum gallium arsenide with a higher concentration of aluminum than in said light-emitting layer; and

said diffusion region comprises a zinc impurity.

16. The light-emitting semiconductor device of claim 14, wherein said conductive semiconductor layer further comprises a second cladding layer, disposed below said light-emitting layer.

17. The light-emitting semiconductor device of claim 16, wherein:

said light-emitting layer comprises aluminum gallium arsenide;

said first cladding layer and said second cladding layer comprise aluminum gallium arsenide with a higher concentration of aluminum than in said light-emitting layer; and

said diffusion region comprises a zinc impurity.

18. The light-emitting semiconductor device of claim 13, further comprising a semi-insulating semiconductor substrate layer disposed below said conductive semiconductor layer.

19. A light-emitting semiconductor array device comprising a matrix-driven plurality of light-emitting semiconductor devices as described in claim 18, the light-emitting semiconductor devices sharing said semi-insulating semiconductor substrate layer.