Behraad Bahreyni,

The following is a recipe that I used to succesfully etch V-grooves in 100 type
silicon wafers with oxide as a mask layer.

Volume of Water - 1000ml
Volume of Isopropyl Alcohol - 250 ml (i.e. 25 % of volume of Water)
20% KOH (204.4 gms)
Temperature of solution was maintained at 80 degrees celsius.

Your best source of reference would be a two - part paper titled "Anisotropic
Etching of Crystalline Silicon in Alkaline Solutions" by H.Seidel, L Csepregi,
A.Heuberger, H. Baumgartel in the Journal of Electrochem. Soc Vol 137 No.11
November 1990.  They have a neat table for different concentration of KOH
solution, at different tempertaure for 100 , 110 and 111 silicon. The etch rate
of 86 microns / hour in the 100 direction  was observed to be consistent with
the results from the paper. Another paper would be "Anisotropic etching of
Silicon" by Kenneth E. Bean in IEEE transactions on Electron Devices, October
1978.

Good luck

Satish Prabhakaran
Graduate Research Associate
Thayer School of Engineering
Dartmouth College
Hanover, NH 03755

Telephone: 603-646-3225