Etching of Silicon - Electrochemistry of Silicon and Its Oxide - page 332

Roughness also changes with many operating conditions. For example, addition
of ppm levels of surfactants can significantly change the etch rate and surface rough-
ness in KOH solutions 1000 and in fluoride-based solutions. 537 Ionic surfactants produce
much smaller roughness than do nonionic surfactants. Roughness that developed in a
BHF solution of 6% HF + 30% can be inhibited by addition of surfactants. 468
Increasing the flow rate of the etchant is found to decrease roughness. 1004 A wafer
growth process which gives different levels of oxygen content has an effect on the
roughness of the etched surface in KOH. 458 Silicon wafer has varied roughness from
one side to the other depending on the position and orientation of the wafer in the
etching tank. 124 Si(111) surface is smoothed on the atomic scale by anodic oxidation in
NaOH followed by oxide stripping in 5% HF, and final stabilization in 40%