You might consider using HNA in the polishing regime every so often
during your KOH etch.

-Mike
  U. of Louisville

>>> Tao  10/05/06 3:42 PM >>>
Hi,
 From my experience, it's hard to get a mirror like (100) or (110)
surface. But (111) surface is always very smooth.
But some people did a good job:
1) http://staff.aist.go.jp/zhen.yang/smooth_etching.htm
2) Fast etching of silicon with a smooth surface in high temperature
ranges near the boiling point of KOH solution TANAKA Hiroshi ;
YAMASHITA Shuichi ; ABE Yoshitsugu ; SHIKIDA Mitsuhiro ; SATO Kazuo
;Sensors and actuators. A, Physical  (Sens. actuators, A Phys.)
 *ISSN* 0924-4247 2004, vol. 114, n^o 2-3, pp. 516-520 [5 page(s)
(article)]

I tested high T etch. I get better surface. But I can't say it's mirror
like. It's just like a mirror with foggy areas.