Chemical--Mechanical Lift-Off Process for InGaN Epitaxial Layers

An InGaN-based light-emitting diode (LED) structure was separated from a GaN/sapphire structure by inserting sacrificial Si-doped InGaN/GaN superlattice layers through a chemical--mechanical lift-off (CMLO) process. The CMLO process consisted of a band-gap-selective photoelectrochemical lateral wet...

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Bibliographic Details
Published inApplied physics express Vol. 4; no. 6; pp. 062101 - 062101-3
Main Authors Lin, Ming-Shiou, Lin, Chia-Feng, Huang, Wan-Chun, Wang, Guei-Miao, Shieh, Bing-Cheng, Dai, Jing-Jie, Chang, Shou-Yi, Wuu, D. S, Liu, Po-Liang, Horng, Ray-Hua
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.06.2011
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Summary:An InGaN-based light-emitting diode (LED) structure was separated from a GaN/sapphire structure by inserting sacrificial Si-doped InGaN/GaN superlattice layers through a chemical--mechanical lift-off (CMLO) process. The CMLO process consisted of a band-gap-selective photoelectrochemical lateral wet etching process and a mechanical lift-off process. A lower elastic modulus and hardness of the lateral-etched LED structure were measured compared with the conventional LED structure, which indicated a weak mechanical property of the treated LED structure. The photoluminescence blue-shift phenomenon and the Raman redshift phenomenon indicated that the compressive strain from the bottom GaN/sapphire structure was released through the CMLO process.
Bibliography:Procedures of the chemical--mechanical lift-off process on the InGaN-based LED structure. (a) Lift-off LED mesa pattern on the adhesive tape and (b) residual bottom GaN layer on the sapphire substrate, observed in the optical microscopy images. The SEM micrographs of (c) lift-off LED mesa patterns on the adhesive tape and (d) cone-shaped structure on the lift-off GaN surface were observed. (a) μ-PL spectra and (b) micro-Raman scattering spectra of the LED structure with and without PEC process, measured at room temperature. Typical load-penetration depth curves of nanoindentation test for the InGaN-based LED structures with and without lateral wet etching process measured to identify the mechanical properties of the LED epitaxial layer.
ISSN:1882-0778
1882-0786
DOI:10.1143/APEX.4.062101