Optical semiconductor device

• US 6,191,436 B1
• Filed: 03/12/1996
• Issued: 02/20/2001
• Est. Priority Date: 03/13/1995
• Status: Expired due to Term

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Shibata, Naoki, Asai, Makoto
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US08/615,858
• Time in Patent Office: 1,806 Days
• Field of Search: 257/91, 257/99, 257/103, 257/745, 257/749
• US Class Current: 257/91
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/145 with a current-blocking structure

Abstract

A LED has a thin highly resistive or insulative layer formed below an electrode pad in order to divert current flow from the region below an electrode pad, which region does not contribute to light emission, to another region which does. Consequently, better current efficiency is obtained. Further, diverting current flow from the region below the electrode pad where mechanical damages are expected deters deterioration of the region. Consequently, the LED lasts longer and is a better quality product.

Claims

1. An optical semiconductor device comprising:

an n-layer having n-conduction type;

a p-layer having p-conduction type formed above said n-layer;

an electrode formed uniformly on substantially the entire surface of said p-layer and capable of passing light therethrough;

an electrode pad for wire bonding located on a portion of said electrode; and

a highly resistive region formed in a part of said p-layer below said electrode pad, wherein said n-layer and said p-layer are made of a nitride compound semiconductor including at least one of aluminum (Al), gallium (Ga), and indium (In), said p-layer is a layer whose resistivity is lowered by annealing or electron beam irradiation said p-layer having an unchanged kind of impurity and an unchanged density of impurity, said highly resistive region is formed by said annealing or electron beam irradiation without lowering the resistivity.

2. An optical semiconductor device of claim 1, wherein said highly resistive region comprises an insulative layer on said p-layer.

3. An optical semiconductor device of claim 2, wherein said optical semiconductor device is a nitride compound light-emitting semiconductor device having at least one of aluminum (Al), gallium (Ga), and indium (In).

4. An optical semiconductor device according to claim 1, wherein said highly resistive region is formed by utilizing a large thermal capacity of said electrode pad so that said electrode pad absorbs and stops conveying heat thereunder.

5. An optical semiconductor device according to claim 1, wherein said highly resistive region is formed by utilizing a large thermal capacity of said electrode pad and an insulative film so that said electrode pad absorbs and stops conveying heat thereunder.

6. An optical semiconductor device according to claim 1, wherein said highly resistive region is formed by irradiating an electron beam to the entire surface using said electrode pad as a mask and by not lowering resistivity of an area shielded by said electrode pad.

7. An optical semiconductor device according to claim 1, wherein said highly resistive region is formed by irradiating an electron beam to the entire surface, using said electrode pad and said insulative film formed on said electrode pad as a mask and by not lowering resistivity of an area shielded by said electrode pad.

8. An optical semiconductor device comprising:

an n-layer having n-conduction type;

a p-layer having p-conduction type formed above said n-layer;

an electrode formed on said p-layer and capable of passing light therethrough;

an electrode pad for wire bonding located on a portion of said electrode;

a highly resistive region located below said electrode pad and having a lateral periphery substantially corresponding in size and shape to a lateral periphery of said electrode pad, wherein said highly resistive region comprises a silicon oxide (SiO₂) layer.

9. An optical semiconductor device of claim 8, wherein said optical semiconductor device is a nitride compound light-emitting semiconductor device having at least one of aluminum (Al), gallium (Ga), and indium (In).