Dear Kagan, In my experience, the use of thermally grown oxide does stand well as etch mask for both TMAH . The oxide etch rate is ~2A/min for TMAH @80C. Thermally grown >3000 A oxide is sufficient as etch mask to etch for 500 um Si substrate of SOI. Regards Om On Thu, May 6, 2010 at 3:44 AM, Kagan Topalliwrote: > Hi, > > PECVD nitride and oxides cannot withstand several hours of KOH or TMAH > etching. LPCVD nitride or thermally grown oxide might be the choices for > masking KOH or TMAH etching. > > Regards. > > -- > Kagan Topalli > Postdoctoral Researcher > ElectroScience Laboratory > The Ohio State University > 1320 Kinnear Road > Columbus, Ohio 43212 > http://www.electroscience.osu.edu/ > e-mail: topalli.1@osu.edu -- Om Krishna Suwal PhD Student Department of Nano-Science Sun Moon University, Research lab- # 104 dong, Interuniversity Semiconductor Research Center, SNU, Shillim Dong, Gwanak Gu,Seoul,151-742 Korea Cellular phone: +82 10 2892 8185