Dry etching characteristics of amorphous As{sub 2}S{sub 3} film in CHF{sub 3} plasma
- Centre for Ultra-high Bandwidth Devices and Optical Systems, Laser Physics Centre, Research School of Physical Science and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia)
The authors describe the dry etching characteristics of amorphous As{sub 2}S{sub 3} films in CHF{sub 3} plasma and the development of an optimized fabrication process for compact waveguides. The observed etching behavior is due to the relative densities of fluorine atoms, polymer precursors, and ions in the plasma which are controlled by the process parameters. In particular, the flow rate of the CHF{sub 3} gas has a significant influence on the etched profile and surface roughness as well as the etch rate of the As{sub 2}S{sub 3}. The profile evolves from isotropic to vertical with the flow rate due to passivation by increasing polymer deposition on the sidewalls. Such passivation also helps achieve smooth sidewalls because it inhibits differential etching between the phases in the inherently phase-separated As{sub 2}S{sub 3} film, which otherwise results in a grainy and rough etched surface. At the highest flow rate, however, excessive polymer deposition occurs and this results in positive-sloped sidewall and grassy etched surface due to micromasking.
- OSTI ID:
- 21179992
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 104; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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