Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes

Wei C. Lee, Kai Ming Uang, Der Ming Kuo, Jui Chiang Chou, Tron M. Chen, Hon Y. Kuo, Shui-Jinn Wang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

A highly reflective ohmic contact and surface roughening by KrF excimer laser technique to improve the optoelectronic properties of high-power Vertical Metallic-substrate GaN-based light-emitting diodes (VM-LEDs) were proposed and investigated. A metal system comprising of Ni/Ag/Ni was employed to serve as a reflector and ohmic contact to p-GaN, which exhibits a good ohmic contact (3.05x10-4 ωcm2) and high reflectivity (89% at the wavelength of 465 nm) after thermal annealing at 500°C in N2 ambient for 10 min. After the removal of sapphire using laser lift-off process (LLO) [1], KrF excimer laser irradiation was adopted to etch the u-GaN layer and then roughen the surface of the exposed n-GaN layer. As compared to regular lateral-structure GaN-based LEDs with ITO transparent conduction layer (TCL), the fabricated VM-LEDs with a chip size of 1000 μmx 1000 demonstrated a typical increase in light output power (Lop) (i.e., ΔLop/Lop) by 325.5% at 350 mA with a decrease in forward voltage (Vf) from 3.67 V down to 3.41 V. As compared to the VM-LEDs with u-GaN etching employing inductively coupled plasma, about 125% enhancement in Lop has been obtained at 350 mA from the proposed samples.

Original languageEnglish
Title of host publication66th DRC Device Research Conference Digest, DRC 2008
Pages141-142
Number of pages2
DOIs
Publication statusPublished - 2008
Event66th DRC Device Research Conference Digest, DRC 2008 - Santa Barbara, CA, United States
Duration: 2008 Jun 232008 Jun 25

Other

Other66th DRC Device Research Conference Digest, DRC 2008
CountryUnited States
CitySanta Barbara, CA
Period08-06-2308-06-25

Fingerprint

Ohmic contacts
Light emitting diodes
Lasers
Excimer lasers
Substrates
Inductively coupled plasma
Laser beam effects
Sapphire
Optoelectronic devices
Etching
Annealing
Wavelength
Electric potential
Metals

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

Cite this

Lee, W. C., Uang, K. M., Kuo, D. M., Chou, J. C., Chen, T. M., Kuo, H. Y., & Wang, S-J. (2008). Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes. In 66th DRC Device Research Conference Digest, DRC 2008 (pp. 141-142). [4800774] https://doi.org/10.1109/DRC.2008.4800774
Lee, Wei C. ; Uang, Kai Ming ; Kuo, Der Ming ; Chou, Jui Chiang ; Chen, Tron M. ; Kuo, Hon Y. ; Wang, Shui-Jinn. / Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes. 66th DRC Device Research Conference Digest, DRC 2008. 2008. pp. 141-142
@inproceedings{78696ac8f83c44b8bc082144a389eb10,
title = "Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes",
abstract = "A highly reflective ohmic contact and surface roughening by KrF excimer laser technique to improve the optoelectronic properties of high-power Vertical Metallic-substrate GaN-based light-emitting diodes (VM-LEDs) were proposed and investigated. A metal system comprising of Ni/Ag/Ni was employed to serve as a reflector and ohmic contact to p-GaN, which exhibits a good ohmic contact (3.05x10-4 ωcm2) and high reflectivity (89{\%} at the wavelength of 465 nm) after thermal annealing at 500°C in N2 ambient for 10 min. After the removal of sapphire using laser lift-off process (LLO) [1], KrF excimer laser irradiation was adopted to etch the u-GaN layer and then roughen the surface of the exposed n-GaN layer. As compared to regular lateral-structure GaN-based LEDs with ITO transparent conduction layer (TCL), the fabricated VM-LEDs with a chip size of 1000 μmx 1000 demonstrated a typical increase in light output power (Lop) (i.e., ΔLop/Lop) by 325.5{\%} at 350 mA with a decrease in forward voltage (Vf) from 3.67 V down to 3.41 V. As compared to the VM-LEDs with u-GaN etching employing inductively coupled plasma, about 125{\%} enhancement in Lop has been obtained at 350 mA from the proposed samples.",
author = "Lee, {Wei C.} and Uang, {Kai Ming} and Kuo, {Der Ming} and Chou, {Jui Chiang} and Chen, {Tron M.} and Kuo, {Hon Y.} and Shui-Jinn Wang",
year = "2008",
doi = "10.1109/DRC.2008.4800774",
language = "English",
isbn = "9781424419425",
pages = "141--142",
booktitle = "66th DRC Device Research Conference Digest, DRC 2008",

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Lee, WC, Uang, KM, Kuo, DM, Chou, JC, Chen, TM, Kuo, HY & Wang, S-J 2008, Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes. in 66th DRC Device Research Conference Digest, DRC 2008., 4800774, pp. 141-142, 66th DRC Device Research Conference Digest, DRC 2008, Santa Barbara, CA, United States, 08-06-23. https://doi.org/10.1109/DRC.2008.4800774

Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes. / Lee, Wei C.; Uang, Kai Ming; Kuo, Der Ming; Chou, Jui Chiang; Chen, Tron M.; Kuo, Hon Y.; Wang, Shui-Jinn.

66th DRC Device Research Conference Digest, DRC 2008. 2008. p. 141-142 4800774.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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T1 - Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes

AU - Lee, Wei C.

AU - Uang, Kai Ming

AU - Kuo, Der Ming

AU - Chou, Jui Chiang

AU - Chen, Tron M.

AU - Kuo, Hon Y.

AU - Wang, Shui-Jinn

PY - 2008

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N2 - A highly reflective ohmic contact and surface roughening by KrF excimer laser technique to improve the optoelectronic properties of high-power Vertical Metallic-substrate GaN-based light-emitting diodes (VM-LEDs) were proposed and investigated. A metal system comprising of Ni/Ag/Ni was employed to serve as a reflector and ohmic contact to p-GaN, which exhibits a good ohmic contact (3.05x10-4 ωcm2) and high reflectivity (89% at the wavelength of 465 nm) after thermal annealing at 500°C in N2 ambient for 10 min. After the removal of sapphire using laser lift-off process (LLO) [1], KrF excimer laser irradiation was adopted to etch the u-GaN layer and then roughen the surface of the exposed n-GaN layer. As compared to regular lateral-structure GaN-based LEDs with ITO transparent conduction layer (TCL), the fabricated VM-LEDs with a chip size of 1000 μmx 1000 demonstrated a typical increase in light output power (Lop) (i.e., ΔLop/Lop) by 325.5% at 350 mA with a decrease in forward voltage (Vf) from 3.67 V down to 3.41 V. As compared to the VM-LEDs with u-GaN etching employing inductively coupled plasma, about 125% enhancement in Lop has been obtained at 350 mA from the proposed samples.

AB - A highly reflective ohmic contact and surface roughening by KrF excimer laser technique to improve the optoelectronic properties of high-power Vertical Metallic-substrate GaN-based light-emitting diodes (VM-LEDs) were proposed and investigated. A metal system comprising of Ni/Ag/Ni was employed to serve as a reflector and ohmic contact to p-GaN, which exhibits a good ohmic contact (3.05x10-4 ωcm2) and high reflectivity (89% at the wavelength of 465 nm) after thermal annealing at 500°C in N2 ambient for 10 min. After the removal of sapphire using laser lift-off process (LLO) [1], KrF excimer laser irradiation was adopted to etch the u-GaN layer and then roughen the surface of the exposed n-GaN layer. As compared to regular lateral-structure GaN-based LEDs with ITO transparent conduction layer (TCL), the fabricated VM-LEDs with a chip size of 1000 μmx 1000 demonstrated a typical increase in light output power (Lop) (i.e., ΔLop/Lop) by 325.5% at 350 mA with a decrease in forward voltage (Vf) from 3.67 V down to 3.41 V. As compared to the VM-LEDs with u-GaN etching employing inductively coupled plasma, about 125% enhancement in Lop has been obtained at 350 mA from the proposed samples.

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U2 - 10.1109/DRC.2008.4800774

DO - 10.1109/DRC.2008.4800774

M3 - Conference contribution

SN - 9781424419425

SP - 141

EP - 142

BT - 66th DRC Device Research Conference Digest, DRC 2008

ER -

Lee WC, Uang KM, Kuo DM, Chou JC, Chen TM, Kuo HY et al. Use of highly reflective ohmic contact and surface KrF laser roughening to improve light output of vertical gan-based light-emitting diodes. In 66th DRC Device Research Conference Digest, DRC 2008. 2008. p. 141-142. 4800774 https://doi.org/10.1109/DRC.2008.4800774