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Proceedings Paper

Cl2/Ar based Inductively Coupled Plasma Etching of GaN/AlGaN Structure
Author(s): D. S. Rawal; Henika Arora; V. R. Agarwal; Ashok Kapoor; Seema Vinayak; B. K. Sehgal; R. Muralidharan; Dipankar Saha; H. K. Malik
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Paper Abstract

Cl2/Ar based inductively coupled plasma etching of GaN/AlGaN is investigated using photoresist mask in a restricted domain of pressure < 10mTorr and RF power <100W, for selective mesa etching. The etch characteristics and rootmean- square surface roughness are studied as a function of process parameters viz. process pressure, Cl2 percentage in total flow rate ratio, and RF bias at a constant ICP power, to achieve moderately high GaN etch rate with anisotropic profiles and smooth surface morphology. The etch rate and resultant rms roughness of etched surface increased with pressure mainly due to dominant reactant limited etch regime. The etch rate also increased with increasing Cl2 % as a result of increased chlorine radicals that enhances chemical etching. The etch rate and rms roughness showed strong dependence on RF power with former increasing and later decreasing with applied RF power up to 80W. The process etch yield variation with applied RF bias is also reported. Negligible etch selectivity was observed between GaN and AlGaN up to 25% aluminum concentration with etch rate ~120nm/min. The studied etch parameters resulted in highly anisotropic mesa structures with Ga rich etched surface.

Paper Details

Date Published: 15 October 2012
PDF: 9 pages
Proc. SPIE 8549, 16th International Workshop on Physics of Semiconductor Devices, 85490L (15 October 2012); doi: 10.1117/12.925529
Show Author Affiliations
D. S. Rawal, Solid State Physics Lab. (India)
Henika Arora, Solid State Physics Lab. (India)
V. R. Agarwal, Solid State Physics Lab. (India)
Ashok Kapoor, Solid State Physics Lab. (India)
Seema Vinayak, Solid State Physics Lab. (India)
B. K. Sehgal, Solid State Physics Lab. (India)
R. Muralidharan, Solid State Physics Lab. (India)
Dipankar Saha, Indian Institute of Technology Bombay (India)
H. K. Malik, Indian Institute of Technology Delhi (India)

Published in SPIE Proceedings Vol. 8549:
16th International Workshop on Physics of Semiconductor Devices
Monica Katiyar; B. Mazhari; Y N Mohapatra, Editor(s)

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