Effect of an in layer on the thermal stability of Ag reflector for vertical GaN-based light-emitting diodes

Woong Sun Yum; Chang Hyeong Lee; Sungho Jin; Tae Yeon Seong

doi:10.1016/j.spmi.2012.12.014

Effect of an in layer on the thermal stability of Ag reflector for vertical GaN-based light-emitting diodes

Woong Sun Yum, Chang Hyeong Lee, Sungho Jin, Tae Yeon Seong

Research output: Contribution to journal › Article › peer-review

14 Citations (Scopus)

Abstract

We investigated the effect of an indium (In) middle layer on the thermal and electrical properties of Ag contacts for high-power GaN-based vertical light-emitting diodes (LEDs). It is shown that with increasing temperature, agglomeration is initiated by the formation of hillocks, followed by the generation of holes, eventually leading to agglomeration. The presence of the In layer effectively delays agglomeration. As a result, the In-combined Ag reflectors exhibit better specific contact resistance (6.0 × 10 ^-5 Ω cm²) and reflectance (∼75% at 440 nm) when annealed at 500 °C, as compared to Ag only contacts. Blue (440 nm) LEDs fabricated with the 500 °C-annealed In-combined Ag contacts exhibit a forward voltage of 2.99 V (at an injection current of 20 mA) lower than that of LEDs with the 500 °C-annealed Ag only contacts. The output power (at 20 mA) of the LEDs with the 500 °C-annealed In-combined Ag contacts is 29% higher than that of LEDs with the 500 °C-annealed Ag only contacts.

Original language	English
Pages (from-to)	77-85
Number of pages	9
Journal	Superlattices and Microstructures
Volume	56
DOIs	https://doi.org/10.1016/j.spmi.2012.12.014
Publication status	Published - 2013

Bibliographical note

Funding Information:
This work was supported a Korea University Grant and the World Class University program through the National Research Foundation of Korea funded by MEST (R33-2008-000-10025-0) and the Industrial Strategic technology development program, 10041878, Development of WPE 75% LED device process and standard evaluation technology funded by the Ministry of Knowledge Economy (Korea).

Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.

Keywords

Ag reflector
GaN
In middle layer
LED
Light output power

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Electrical and Electronic Engineering

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10.1016/j.spmi.2012.12.014

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title = "Effect of an in layer on the thermal stability of Ag reflector for vertical GaN-based light-emitting diodes",

abstract = "We investigated the effect of an indium (In) middle layer on the thermal and electrical properties of Ag contacts for high-power GaN-based vertical light-emitting diodes (LEDs). It is shown that with increasing temperature, agglomeration is initiated by the formation of hillocks, followed by the generation of holes, eventually leading to agglomeration. The presence of the In layer effectively delays agglomeration. As a result, the In-combined Ag reflectors exhibit better specific contact resistance (6.0 × 10 -5 Ω cm2) and reflectance (∼75% at 440 nm) when annealed at 500 °C, as compared to Ag only contacts. Blue (440 nm) LEDs fabricated with the 500 °C-annealed In-combined Ag contacts exhibit a forward voltage of 2.99 V (at an injection current of 20 mA) lower than that of LEDs with the 500 °C-annealed Ag only contacts. The output power (at 20 mA) of the LEDs with the 500 °C-annealed In-combined Ag contacts is 29% higher than that of LEDs with the 500 °C-annealed Ag only contacts.",

keywords = "Ag reflector, GaN, In middle layer, LED, Light output power",

author = "Yum, {Woong Sun} and Lee, {Chang Hyeong} and Sungho Jin and Seong, {Tae Yeon}",

note = "Funding Information: This work was supported a Korea University Grant and the World Class University program through the National Research Foundation of Korea funded by MEST (R33-2008-000-10025-0) and the Industrial Strategic technology development program, 10041878, Development of WPE 75% LED device process and standard evaluation technology funded by the Ministry of Knowledge Economy (Korea). Copyright: Copyright 2013 Elsevier B.V., All rights reserved.",

year = "2013",

doi = "10.1016/j.spmi.2012.12.014",

language = "English",

volume = "56",

pages = "77--85",

journal = "Superlattices and Microstructures",

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AU - Yum, Woong Sun

AU - Lee, Chang Hyeong

AU - Jin, Sungho

AU - Seong, Tae Yeon

N1 - Funding Information: This work was supported a Korea University Grant and the World Class University program through the National Research Foundation of Korea funded by MEST (R33-2008-000-10025-0) and the Industrial Strategic technology development program, 10041878, Development of WPE 75% LED device process and standard evaluation technology funded by the Ministry of Knowledge Economy (Korea). Copyright: Copyright 2013 Elsevier B.V., All rights reserved.

PY - 2013

Y1 - 2013

N2 - We investigated the effect of an indium (In) middle layer on the thermal and electrical properties of Ag contacts for high-power GaN-based vertical light-emitting diodes (LEDs). It is shown that with increasing temperature, agglomeration is initiated by the formation of hillocks, followed by the generation of holes, eventually leading to agglomeration. The presence of the In layer effectively delays agglomeration. As a result, the In-combined Ag reflectors exhibit better specific contact resistance (6.0 × 10 -5 Ω cm2) and reflectance (∼75% at 440 nm) when annealed at 500 °C, as compared to Ag only contacts. Blue (440 nm) LEDs fabricated with the 500 °C-annealed In-combined Ag contacts exhibit a forward voltage of 2.99 V (at an injection current of 20 mA) lower than that of LEDs with the 500 °C-annealed Ag only contacts. The output power (at 20 mA) of the LEDs with the 500 °C-annealed In-combined Ag contacts is 29% higher than that of LEDs with the 500 °C-annealed Ag only contacts.

AB - We investigated the effect of an indium (In) middle layer on the thermal and electrical properties of Ag contacts for high-power GaN-based vertical light-emitting diodes (LEDs). It is shown that with increasing temperature, agglomeration is initiated by the formation of hillocks, followed by the generation of holes, eventually leading to agglomeration. The presence of the In layer effectively delays agglomeration. As a result, the In-combined Ag reflectors exhibit better specific contact resistance (6.0 × 10 -5 Ω cm2) and reflectance (∼75% at 440 nm) when annealed at 500 °C, as compared to Ag only contacts. Blue (440 nm) LEDs fabricated with the 500 °C-annealed In-combined Ag contacts exhibit a forward voltage of 2.99 V (at an injection current of 20 mA) lower than that of LEDs with the 500 °C-annealed Ag only contacts. The output power (at 20 mA) of the LEDs with the 500 °C-annealed In-combined Ag contacts is 29% higher than that of LEDs with the 500 °C-annealed Ag only contacts.

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KW - In middle layer

KW - LED

KW - Light output power

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Effect of an in layer on the thermal stability of Ag reflector for vertical GaN-based light-emitting diodes

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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