# US 9,437,776 B2 · Method for manufacturing light emitting diodes with smooth surface for reflective electrode

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- Number: US 9,437,776 B2
- Document ID: US9437776B2
- Status: Granted
- Kind: B2
- Application number: 14/085,581
- Filed: 2013-11-20
- Published: 2014-03-20
- Granted: 2016-09-06
- Earliest claimed: 2008-03-31
- Assignees: Kabushiki Kaisha Toshiba
- Applicants: Toshiba Corporation
- Inventors: Chao-Kun Lin; Heng Liu
- Web page: https://patentgrep.com/patent/US9437776B2

## CPC

- H10H 20/83: Electrodes
- H10H 20/82: Roughened surfaces, e.g. at the interface between epitaxial layers
- H10H 20/018: {Bonding of wafers}
- H10H 20/825: containing nitrogen, e.g. GaN
- H10H 20/833: Transparent materials
- H10W 72/07252: {changes in structures or sizes}
- H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps
- H10W 72/227: {Multiple bumps having different sizes}
- H10W 72/90: Bond pads, in general
- H10W 72/926: {Multiple bond pads having different sizes}
- H10W 72/9415: {relative to the surface, e.g. recessed, protruding}
- H10W 72/944: {Dispositions of multiple bond pads}
- H10W 90/724: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A light emitting diode comprising an epitaxial layer structure, a first electrode, and a second electrode. The first and second electrodes are separately disposed on the epitaxial layer structure, and the epitaxial layer structure has a root-means-square (RMS) roughness less than about 3 at a surface whereon the first electrode is formed.

## Claims

### Claim 1

A method for manufacturing a light emitting diode, comprising:
forming an epitaxial layer structure, comprising a first epitaxial layer and a second epitaxial layer; and
depositing a first electrode on the first epitaxial layer of the epitaxial layer structure;
depositing a transparent ohmic contact layer on the second epitaxial layer of the epitaxial structure; and
depositing a second electrode on the transparent ohmic contact layer, wherein the transparent ohmic contact layer has a root-means-square (RMS) roughness less than about 3 nm at a surface whereon the second electrode is deposited.

### Claim 2 (depends on 1)

The method of claim 1, wherein the second electrode is formed by depositing metals including at least one selected from a group consisting of Ag, Pt, Ni, Cr, Ti, Al, Pd, W, Ru, Rh, Mo, and their alloys.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first epitaxial layer is an n-type epitaxial layer and the second epitaxial layer is a p-type epitaxial layer.

### Claim 4 (depends on 3)

The method of claim 3, wherein the first electrode is an n-type electrode and wherein the second electrode is a p-type electrode.

### Claim 5 (depends on 3)

The method of claim 3, further comprising forming an active layer between the n-type epitaxial layer and the p-type epitaxial layer.

### Claim 6 (depends on 1)

The method of claim 1, wherein the second epitaxial layer is formed at a temperature no less than 950° C. at a growth rate no more than 150 Å/min.

### Claim 7 (depends on 1)

The method of claim 1, wherein the first and second electrodes are deposited on opposite sides of the epitaxial layer structure.

### Claim 8

A method for manufacturing a light emitting diode, comprising:
forming an epitaxial layer structure, comprising a first epitaxial layer and a second epitaxial layer; and
depositing a first electrode on the first epitaxial layer of the epitaxial layer structure;
depositing a transparent ohmic contact layer on the second epitaxial layer of the epitaxial structure; and
depositing a second electrode on the transparent ohmic layer, wherein:
the transparent ohmic contact layer has a root-means-square (RMS) roughness less than about 3 nm at a surface whereon the second electrode is deposited, and
the light emitting diode is a vertical light emitting diode device.

### Claim 9 (depends on 7)

The method of claim 7, wherein the second electrode is mounted on a sub-mount substrate.

### Claim 10 (depends on 9)

The method of claim 9, wherein the substrate is selected from a group consisting of a metal, a semiconductor material, and a ceramic.

### Claim 11

A method for manufacturing a light emitting diode, comprising:
forming an epitaxial layer structure, comprising a first epitaxial layer and a second epitaxial layer;
depositing a first electrode on the first epitaxial layer of the epitaxial layer structure;
depositing a transparent ohmic contact layer on the second epitaxial layer of the epitaxial layer structure; and
depositing a second electrode on the transparent ohmic contact layer, wherein:
the transparent ohmic contact layer has a root-means-square (RMS) roughness less than about 3 nm at a surface whereon the second electrode is deposited,
the second electrode is mounted on a sub-mount substrate, and
the substrate is selected from a group consisting of Cu, Mo, W, Al, Si, GaAs, GaP, InP, Ge, Al2O3 and AlN.

### Claim 12 (depends on 1)

The method of claim 1, wherein the epitaxial layer structure is formed on a substrate, and the first and second electrodes are deposited on a same side of the substrate.

### Claim 13 (depends on 1)

The method of claim 1, wherein the second epitaxial layer is formed by MOCVD (Metal-Organic Chemical Vapor Deposition).

### Claim 14 (depends on 13)

The method of claim 13, wherein the second epitaxial layer is formed at a temperature no less than 950° C. at a growth rate no more than 150 Å/min.