High density plasma reactive ion etching of CoFeB magnetic thin films using a CH4/Ar plasma

Title
High density plasma reactive ion etching of CoFeB magnetic thin films using a CH4/Ar plasma
Authors
김은호이태영민병철정지원
Keywords
CoFeB thin films; Ti hard mask; Magnetic tunnel junction; Inductively coupled plasma reactive ion; etching; CH4/O2/Ar gas
Issue Date
2012-10
Publisher
Thin solid films
Citation
VOL 521, 216-221
Abstract
In this study, high density plasma reactive ion etching of CoFeB magnetic thin films was investigated using CH4/Ar and CH4/O2/Ar gas mixes. The etch rate, etch selectivity and etch profile of CoFeB thin films were obtained as a function of gas concentration and etch parameters. The etch rate of CoFeB thin films and Ti hard mask gradually decreased with increasing CH4 or O2 concentrations. As the CH4 gas was added to Ar gas, the etch profile of the CoFeB thin films improved. The addition of O2 gas into the CH4/Ar gas mix also led to anisotropic etching of the CoFeB thin films. With an increase in the dc-bias voltage supplied to the substrate and a decrease in gas pressure, the etch rates increased and the etch profile became vertical without any redepositions or etch residues. Based on the etch characteristics and surface analysis of the etched films by X-ray photoelectron spectroscopy, it can be concluded that the etch mechanism of CoFeB thin films in CH4/Ar and CH4/O2/Ar plasmas does not follow the reactive ion etch mechanism but rather a chemically assisted physical sputtering mechanism.
URI
http://pubs.kist.re.kr/handle/201004/43229
ISSN
00406090
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KIST Publication > Article
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