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Title: Ultradeep electron cyclotron resonance plasma etching of GaN

Here, ultradeep (≥5 μm) electron cyclotron resonance plasma etching of GaN micropillars was investigated. Parametric studies on the influence of the applied radio-frequency power, chlorine content in a Cl 2/Ar etch plasma, and operating pressure on the etch depth, GaN-to-SiO 2 selectivity, and surface morphology were performed. Etch depths of >10 μm were achieved over a wide range of parameters. Etch rates and sidewall roughness were found to be most sensitive to variations in RF power and % Cl 2 in the etch plasma. Selectivities of >20:1 GaN:SiO 2 were achieved under several chemically driven etch conditions where a maximum selectivity of ~39:1 was obtained using a 100% Cl 2 plasma. The etch profile and (0001) surface morphology were significantly influenced by operating pressure and the chlorine content in the plasma. Optimized etch conditions yielded >10 μm tall micropillars with nanometer-scale sidewall roughness, high GaN:SiO 2 selectivity, and nearly vertical etch profiles. These results provide a promising route for the fabrication of ultradeep GaN microstructures for use in electronic and optoelectronic device applications. In addition, dry etch induced preferential crystallographic etching in GaN microstructures is also demonstrated, which may be of great interest for applications requiring access to non- ormore » semipolar GaN surfaces.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-730843
Journal ID: ISSN 0734-2101
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films
Additional Journal Information:
Journal Volume: 35; Journal Issue: 6; Journal ID: ISSN 0734-2101
Publisher:
American Vacuum Society
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 36 MATERIALS SCIENCE
OSTI Identifier:
1389946
Alternate Identifier(s):
OSTI ID: 1372593

Harrison, Sara E., Voss, Lars F., Torres, Andrea M., Frye, Clint D., Shao, Qinghui, and Nikolic, Rebecca J.. Ultradeep electron cyclotron resonance plasma etching of GaN. United States: N. p., Web. doi:10.1116/1.4994829.
Harrison, Sara E., Voss, Lars F., Torres, Andrea M., Frye, Clint D., Shao, Qinghui, & Nikolic, Rebecca J.. Ultradeep electron cyclotron resonance plasma etching of GaN. United States. doi:10.1116/1.4994829.
Harrison, Sara E., Voss, Lars F., Torres, Andrea M., Frye, Clint D., Shao, Qinghui, and Nikolic, Rebecca J.. 2017. "Ultradeep electron cyclotron resonance plasma etching of GaN". United States. doi:10.1116/1.4994829. https://www.osti.gov/servlets/purl/1389946.
@article{osti_1389946,
title = {Ultradeep electron cyclotron resonance plasma etching of GaN},
author = {Harrison, Sara E. and Voss, Lars F. and Torres, Andrea M. and Frye, Clint D. and Shao, Qinghui and Nikolic, Rebecca J.},
abstractNote = {Here, ultradeep (≥5 μm) electron cyclotron resonance plasma etching of GaN micropillars was investigated. Parametric studies on the influence of the applied radio-frequency power, chlorine content in a Cl2/Ar etch plasma, and operating pressure on the etch depth, GaN-to-SiO2 selectivity, and surface morphology were performed. Etch depths of >10 μm were achieved over a wide range of parameters. Etch rates and sidewall roughness were found to be most sensitive to variations in RF power and % Cl2 in the etch plasma. Selectivities of >20:1 GaN:SiO2 were achieved under several chemically driven etch conditions where a maximum selectivity of ~39:1 was obtained using a 100% Cl2 plasma. The etch profile and (0001) surface morphology were significantly influenced by operating pressure and the chlorine content in the plasma. Optimized etch conditions yielded >10 μm tall micropillars with nanometer-scale sidewall roughness, high GaN:SiO2 selectivity, and nearly vertical etch profiles. These results provide a promising route for the fabrication of ultradeep GaN microstructures for use in electronic and optoelectronic device applications. In addition, dry etch induced preferential crystallographic etching in GaN microstructures is also demonstrated, which may be of great interest for applications requiring access to non- or semipolar GaN surfaces.},
doi = {10.1116/1.4994829},
journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
number = 6,
volume = 35,
place = {United States},
year = {2017},
month = {7}
}