GaP-base semiconductor light emitting device

• US 20030047745A1
• Filed: 08/27/2002
• Published: 03/13/2003
• Est. Priority Date: 08/31/2001
• Status: Active Grant

• Current Assignee: Shin-Etsu Handotai Co., Ltd. (Shin-Etsu Chemical Company Limited)
• Original Assignee: Shin-Etsu Handotai Co., Ltd. (Shin-Etsu Chemical Company Limited)
• Inventors: Kaneko, Yasutsugu, Ikeda, Hitoshi, Suzuki, Kingo
• Granted Patent: US 6,700,139 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• 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 2224/45144 Gold (Au) as principal constituent
• 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 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 24/32 of an individual layer connector
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table

Abstract

The main surface on the side of a p-type layer of a GaP-base semiconductor is defined as a first main surface, and the main surface opposite thereto as a second main surface. The second main surface is lapped and then etched using aqua regia to thereby collectively form thereon specular concave curved surfaces which swell inwardly into the semiconductor substrate in order to enhance total reflection of light. On the other hand, the area on the surface of semiconductor substrate excluding that for forming a first contact layer and excluding the second main surface are subjected to anisotropic etching to thereby collectively form outwardly-swelling convex curved surfaces in order to reduce total reflection of light. A second contact layer (second electrode) to be formed on the second main surface is composed of an alloy of Au, Si and Ni, and a first contact layer to be formed on the first main surface is composed of an alloy of Au as combined with either of Be and Zn. This successfully provides a GaP-base semiconductor light emitting device which can ensure a satisfactory level of improvement in the luminance even though the emission mechanism thereof relies upon indirect transition.

Claims

1. A GaP-base semiconductor light emitting device comprising a GaP-base semiconductor substrate internally having a p-n junction formed between a p-type layer and n-type layer, and electrodes for applying drive voltage for light emission to the semiconductor substrate, wherein

a first main surface, which is defined as a main surface on the side of the p-type layer of the semiconductor substrate, and side surface thereof have a form of rough surface which comprises a collective of outwardly-swelling convex curved surfaces, and

a second main surface, which is defined as a main surface on the side of the n-type layer, has a form of specular surface finished by etching using aqua regia.

2. The GaP-base semiconductor light emitting device according to claim 1, wherein the second main surface has a form of specular surface comprising a collective of specular concave curved surfaces, each of which swelling inwardly into the semiconductor substrate.

3. The GaP-base semiconductor light emitting device according to claim 1, wherein the second main surface has a form of specular surface formed by lapping and successive etching using aqua regia.

4. The GaP-base semiconductor light emitting device according to claim 2, wherein the second main surface has a form of specular surface formed by lapping and successive etching using aqua regia.

5. The GaP-base semiconductor light emitting device according to claim 2, wherein the concave curved surface has a diameter of curvature of 5 μ

m to 150 μ

m, and an inward depth of 0.5 μ

m to 15 μ

m.

6. The GaP-base semiconductor light emitting device according to claim 1, wherein the semiconductor substrate is bonded to an electrode support member so that the entire portion of the second main surface thereof is covered with an electro-conductive paste.

7. The GaP-base semiconductor light emitting device according to claim 1, wherein the electrodes formed on the second main surface has a contact layer comprising an alloy of Au, Si and Ni.

8. The GaP-base semiconductor light emitting device according to claim 1, wherein the electrodes formed on the first main surface has a contact layer comprising an alloy of Au as combined with either of Be and Zn.

9. A GaP-base semiconductor light emitting device comprising a GaP semiconductor substrate internally having a p-n junction formed between a p-type layer and n-type layer, and electrodes for applying drive voltage for light emission to said GaP semiconductor substrate, wherein

a first main surface, which is defined as a main surface on the side of the p-type layer of the GaP semiconductor substrate, and side surface thereof have a form of rough surface which comprises a collective of outwardly-swelling convex curved surfaces,

a second main surface, which is defined as a main surface on the side of the n-type layer, is made into a specular surface which comprises a collective of specular concave curved surfaces,

the electrodes formed on the first main surface has a contact layer comprising an alloy of Au as combined with either of Be and Zn,

the electrodes formed on the second main surface have a contact layer comprising an alloy of Au, Si and Ni, and

the semiconductor substrate is bonded to an electrode support member so that the entire portion of the second main surface thereof is covered with an electro-conductive paste.

10. A GaP-base semiconductor light emitting device according to claim 9, wherein the second main surface has a form of specular surface formed by lapping and successive etching using aqua regia.