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Title: Comparative study of GaN mesa etch characteristics in Cl{sub 2} based inductively coupled plasma with Ar and BCl{sub 3} as additive gases

GaN thin film etching is investigated and compared for mesa formation in inductively coupled plasma (ICP) of Cl{sub 2} with Ar and BCl{sub 3} gas additives using photoresist mask. Etch characteristics are studied as a function of ICP process parameters, viz., ICP power, radio frequency (RF) power, and chamber pressure at fixed total flow rate. The etch rate at each ICP/RF power is 0.1–0.2 μm/min higher for Cl{sub 2}/Ar mixture mainly due to higher Cl dissociation efficiency of Ar additive that readily provides Cl ion/radical for reaction in comparison to Cl{sub 2}/BCl{sub 3} mixture. Cl{sub 2}/Ar mixture also leads to better photoresist mask selectivity. The etch-induced roughness is investigated using atomic force microscopy. Cl{sub 2}/Ar etching has resulted in lower root-mean-square roughness of GaN etched surface in comparison to Cl{sub 2}/BCl{sub 3} etching due to increased Ar ion energy and flux with ICP/RF power that enhances the sputter removal of etch product. The GaN surface damage after etching is also evaluated using room temperature photoluminescence and found to be increasing with ICP/RF power for both the etch chemistries with higher degree of damage in Cl{sub 2}/BCl{sub 3} etching under same condition.
Authors:
; ; ;  [1]
  1. Solid State Physics Laboratory, Lucknow Road, Timarpur, Delhi-110054 (India)
Publication Date:
OSTI Identifier:
22258788
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 32; Journal Issue: 3; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ADDITIVES; ARGON IONS; ATOMIC FORCE MICROSCOPY; BORON CHLORIDES; CHLORINE; CHLORINE IONS; COMPARATIVE EVALUATIONS; ETCHING; FLOW RATE; GALLIUM NITRIDES; INDIUM CHLORIDES; MIXTURES; PHOTOLUMINESCENCE; PLASMA; RADIOWAVE RADIATION; ROUGHNESS; SURFACES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS