Correlation of the anisotropic etching of single−crystal silicon spheres and wafers

Abstract

Studies of the anisotropic etching of silicon single−crystal wafers and spheres were conducted using 10−M potassium hydroxide as the etchant. The etch rates along the major slow−etch directions were measured. The sides of circular mesas etched into (111), (110), and (100) wafers were found to be inclined to the wafer surface. The angles of inclination varied with azimuthal position and could be correlated with the slow−etch directions measured from an etched sphere. A method was developed to predict these angles of inclination for surfaces of varied orientation using the rate of etching data and angular measurements from an etched sphere.