A Simple Concave Corner Compensation of Etched Si(100) in 25 wt % TMAH Water Solution

In this paper, a new concave corner compensation for etching of (100) silicon substrates in 25 wt % TMAH water solution at the temperature of 80°C is presented and analysed. The aim of developed technique is to reduce area of the etched {111} planes when there is a need to obtain 3D silicon structures with sidewalls vertical to substrate's surface. Appearance of the slow etching {111} planes cannot be eliminated. All crystallographic planes that appeared during evolution of etched compensations are determined. All the parameters necessary to apply developed concave corner compensation in various designs are provided. As a result, the side along the < 11 0> crystallographic direction in the masking layer of the unwanted {111} planes is reduced approximately 3 times.