Semiconductor light emitting device with blocking layer

• US 5,744,828 A
• Filed: 07/10/1996
• Issued: 04/28/1998
• Est. Priority Date: 07/13/1995
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Unno, Kazumi, Nishitani, Katsuhiko, Nozaki, Hideki, Idei, Yasuo
• Primary Examiner(s): MINTEL, WILLIAM A
• Application Number:
  US08/678,626
• Time in Patent Office: 657 Days
• Field of Search: 257/98, 257/94, 257/95, 257/96, 257/97, 257/99, 372/49, 372/46, 372/99
• US Class Current: 257/94
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/38 with a particular shape

Abstract

A semiconductor light emitting device has a semiconductor substrate (1). On a first principal plane of the substrate, an emission layer is formed. In a predetermined region on the emission layer, a current blocking layer (10) is formed. On the current blocking layer, an excitation electrode (20) is formed. A substrate electrode (9) is formed on a second principal plane of the substrate. The excitation electrode is composed of a bonding pad (21) and a current supply electrode (22). The current blocking layer is under the bonding pad. The current blocking layer prevents a current from flowing under the bonding pad. The current supply electrode improves the light emission efficiency of the device.

Claims

1. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer and current blocking layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode, said current blocking layer being under the bonding pad,

wherein said current supply electrode extends along the periphery of said semiconductor substrate and said bonding pad is located inside of said current supply electrode with a light emission surface between said current supply electrode and said bonding pad through which light is passed.

2. The device as claimed in claim 1, further comprising a reflection layer formed between the first principal plane of said semiconductor substrate and said emission layer.

3. The device as claimed in claim 2, further comprising a current diffusion layer formed on said emission layer.

4. The device as claimed in claim 3, further comprising a contact layer formed between one of said emission layer and current diffusion layer and said excitation electrode and current blocking layer.

5. The device as claimed in claim 4, wherein the top surface of the device except the bonding pad serves as an emission plane, and the ratio of the area of the current supply electrode to the area of the emission plane is equal to or smaller than 25%.

6. The device as claimed in claim 5, wherein the current supply electrode consists of quadrangle frames that surround the bonding pad and are electrically connected to the bonding pad.

7. The device as claimed in claim 5, wherein the current supply electrode consists of a quadrangle frame extending along the periphery of the contact layer.

8. The device as claimed in claim 2, wherein said current blocking layer is formed entirely on said contact layer except under the current supply electrode.

9. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode strip, said current blocking layer being under the bonding pad;

wherein said current supply electrode strip extends along the periphery of said semiconductor substrate with a light passing surface through which light is passed inside of said current supply electrode strip, and said bonding pad is located outside of said current supply electrode and said light passing surface.

10. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer and current blocking layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode, said current blocking layer being under the bonding pad;

wherein said current blocking layer is formed in one area on the contact layer, and the emission plane is formed in another area on the contact layer.

11. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer and current blocking layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode, said current blocking layer being under the bonding pad;

wherein said current blocking layer is formed in one area on the contact layer, and the emission plane is formed in another area on the contact layer; and

wherein said current blocking layer has a thickness equal to or greater than 0.1 μ

m.

12. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer and current blocking layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode, said current blocking layer being under the bonding pad;

wherein said current blocking layer is formed in one area on the contact layer, and the emission plane is formed in another area on the contact layer; and

wherein the current supply electrode includes a quadrangle frame.

13. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer and current blocking layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode, said current blocking layer being under the bonding pad;

wherein said current blocking layer is formed in one area on the contact layer, and the emission plane is formed in another area on the contact layer; and

wherein the current supply electrode has a T shape.

14. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer and current blocking layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode, said current blocking layer being under the bonding pad;

wherein said current blocking layer is formed in one area on the contact layer, and the emission plane is formed in another area on the contact layer; and

wherein the current supply electrode has a cross shape.

15. A semiconductor light emitting device comprising:

a semiconductor substrate;

an emission layer formed on a first principal plane of said semiconductor substrate and having a plurality of semiconductor films;

a current blocking layer formed in a predetermined region on said emission layer;

an excitation electrode formed on said emission layer and current blocking layer; and

a substrate electrode formed on a second principal plane of said semiconductor substrate, said excitation electrode having a bonding pad for connection to a bonding wire that passes an external current, and a current supply electrode, said current blocking layer being under the bonding pad;

wherein said current blocking layer is formed in one area on the contact layer, and the emission plane is formed in another area on the contact layer;

wherein the current supply electrode has a cross shape; and

wherein said semiconductor substrate is a GaAs compound semiconductor substrate, and said emission layer is made of a four-element compound semiconductor containing In, Ga, Al, and P.