Photoelectrochemical Fabrication of Gratings in SiC
Abstract
Photochemical etching has been demonstrated as a means for generating high resolution patterns in silicon carbide. Both CVD and epitaxial (on Si) SiC were used. Liquid electrolytes containing either fluoride or ethylene diamine were found to promote smooth photoanodic dissolution, without passivation. Very low anodic dark currents permitted the highest degree of spatial selectivity in the epitaxial material, although patterned photoetching of CVD-SiC could be achieved under high light intensity. Diffraction gratings were demonstrated by defining the grating structure in photoresist on the electrode surface, then photoetching the spaces exposed to the electrolyte. SiC has considerable significance as a substrate for gratings in the vacuum ultraviolet and x-ray wavelengths due to its high reflectance in these regions. Additionally, it has a high degree of stability against thermal degradation and radiation damage, making it a choice material for high power laser optics. Because of the extreme hardness of SiC, it is difficult to fabricate gratings by ruling. The photoelectrochemical method demonstrated here is a simple one-step technique that should be adaptable to large area CVD epitaxial SiC substrates that are available commercially.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1989
- Accession Number
- ADA208992
Entities
People
- Jianguo Li
- John P. Hachey
- Michael M. Carrabba
- R. D. Rauh
- Yaonan Wang