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Anisotropic wet etching of a novel micro-texture structure for an Al/n-Si/Al metal-semiconductor-metal photodetector fabrication
Author(s)
Suttijalern, Kamonwan
Niemcharoen, Surasak
Date Issued
August 1, 2021
Type
Article
Abstract
Micro-electro-mechanical system fabrication involves molding on a single substrate. Chemical wet etching is common in these systems because it can provide a very high etch rate and selectivity. This optical device has been successfully completed fabrication by using the single-step lithography process. The surface was coated with PR and patterned using a single mask to create U-shaped structures by a wide electrode gap on a silicon substrate. Then it was etched using anisotropic wet etching process in potassium hydroxide, tetramethylammonium hydroxide (TMAH), silicic acid and dissolved silicon powder. The etchant created a 58% increase in the light sensitive area of the U-shaped trench in the structure higher compared to the planar structure. Random micro-pyramids, formed on the silicon surface in the U-shaped structure by the silicic acid-added TMAH solution, led to a ∼254 times higher ratio between photon generated current and dark current at reverse bias. This processing technique is a promising technology for improving performance for next-generation optical sensors or silicon photodetector.
Citation
Journal of Micromechanics and Microengineering, 31(8), 2021