The cross-sectional geometry produced by anisotropic etching high aspe
ct ratio (height/width = 115) silicon grooves with CsOH was studied as
a function of the solution concentration. At 50 weight percent (w/o)
CsOH straight sidewalls are produced, but at 15 and 25 w/o re-entrant
tapered profiles are produced. The etch rates are increased in the gro
ove by 25-100% indicating diffusion effects. The etch rate of the surf
ace was in agreement with previous studies of CsOH etching, but unable
to predict the dimensional changes in the grooves.