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Ellipsometric Monitoring of Defects Induced by Electron Cyclotron Resonance Etching of GaAs

Published online by Cambridge University Press:  26 February 2011

P. G. Snyder
Affiliation:
Center for Microelectronic and Optical Materials Research, and Dept. of Electrical Engineering, U. Nebraska-Lincoln, Lincoln, NE 68588–0511
N. J. Ianno
Affiliation:
Center for Microelectronic and Optical Materials Research, and Dept. of Electrical Engineering, U. Nebraska-Lincoln, Lincoln, NE 68588–0511
B. Wigert
Affiliation:
Center for Microelectronic and Optical Materials Research, and Dept. of Electrical Engineering, U. Nebraska-Lincoln, Lincoln, NE 68588–0511
S. Pittal
Affiliation:
J.A. Woollam Co., Suite 39, 650 J St., Lincoln, NE 68508
B. Johs
Affiliation:
J.A. Woollam Co., Suite 39, 650 J St., Lincoln, NE 68508
J. A. Woollam
Affiliation:
J.A. Woollam Co., Suite 39, 650 J St., Lincoln, NE 68508
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Abstract

Spectroscopic ellipsometry (SE) measurements were made during and after electron cyclotron resonance (ECR) etching of GaAs. The spectral range for ex situ measurements, 1.24–5 eV, included the E1, E1+A1 critical points. The Ej, Ei+Aj structure was red shifted by about 50 meV, and broadened, by etching with a mixture of methane, argon, and hydrogen. Exposure to a pure H2 plasma caused greater red shifting and broadening, while a pure Ar ECR plasma produced only a slight red shift. The red shift is consistent with an increase in lattice constant of the order of 1%, in the top 10-30 nm. Broadening is consistent with crystalline lattice damage.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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