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Proceedings Paper

Fabrication of surface gratings in GaAs and AlGaAs by electron beam lithography and chemically assisted ion beam etching
Author(s): Jens Dienelt; Karsten Otte; Klaus-Peter Zimmer; F. Pietag; Frieder Bigl
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Paper Abstract

Optical surface gratings for surface emitting semiconductor lasers require extremely smooth functional surfaces, vertical step edges, a low sidewall roughness, and a high accuracy cover a large are. We report on the fabrication of binary patterns with a period of 1300 nm in GaAs and AlGaAs by electron beam lithography and different dry etching techniques, such as IBE, CAIBE and CARIBE. In order to improve the selectivity of the etch technique as well as the sidewall roughness three different etching mask techniques were applied. For grating depths of about 150 nm the best result with respect other geometrical grating characteristics have been achieved by using the e-beam exposed and developed PMMA as a direct etching mask. Comparing the different etching techniques, CAIBE on GaAs with chlorine shows the best etching behavior. A step edge angle of 90 degrees was achieved at an energy of 200 eV and a chlorine flow of 1.25 sccm. Optical diffraction measurements reveal a high efficiency for the gratings with vertical sidewalls and a line/space ratio of approximately 1.

Paper Details

Date Published: 6 September 1999
PDF: 11 pages
Proc. SPIE 3739, Optical Fabrication and Testing, (6 September 1999); doi: 10.1117/12.360145
Show Author Affiliations
Jens Dienelt, Institute of Surface Modification (Germany)
Karsten Otte, Institute of Surface Modification (Germany)
Klaus-Peter Zimmer, Institute of Surface Modification (Germany)
F. Pietag, Institute of Surface Modification (Germany)
Frieder Bigl, Institute of Surface Modification (Germany)

Published in SPIE Proceedings Vol. 3739:
Optical Fabrication and Testing
Roland Geyl; Jonathan Maxwell, Editor(s)

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