POROUS SILICON FABRICATION PROCESS FOR OPTICAL REFLECTORS
DOI:
https://doi.org/10.53555/eijas.v4i2.65Keywords:
Porous silicon, non-manhattan, high aspect ratio, MEMS, wet etchingAbstract
We describe the use of porous silicon fabrication technique for fabricating non-manhattan structures in silicon using wet etching. The fabrication method is simple to set up, economical and produces smooth etched surface. A solid source diffusion of N++ in a P type wafer with low stress thermally grown silicon nitride is used as a masking layer. Comparison of porous silicon etches with wafers solid source diffusion and implanted diffusion is presented. The result show that areas where a solid source diffusion is used form an etch angle of 70-80°, however using an implanted diffusion the etch angle is closer to 90°. The selectivity of the etch during porous silicon fabrication using any of the above two as masking layer results in fabrication of high aspect ratio non-manhattan structures. These structures since are wet etched do not have surface roughness and can be used for optical applications.
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