> I would like to know if anyone has done or know of some
> results of the etch
> rate of 111 planes in silicon, in KOH. The values I've found in the
> literature seems too low.

If you're seeing an apparent higher etch rate of {111} planes,
it could be due to etching at the edge of the mask or undercutting of the
mask.
Not having perfect alignment of the edges of the opening in the mask
to the flat (the [110] direction) will also result in a larger KOH etch pit,
which may appear to give faster etching of {111} planes.

        --Kirt Williams Agilent Technologies