Xing: Note that the flat on a silicon wafer is a <110> direction, not a <100> direction, so the sides of your pits should be parallel and perpendicular to the flat. Maybe that's the source of the confusion. The surface of an (001) wafer points in the [001] direction. --Kirt Williams -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Xing Sheng Sent: Thursday, March 01, 2012 4:30 PM To: mems-talk Subject: Re: [mems-talk] silicon KOH etch That was what I expected. However, I still get a pit of size d^2 along 100 direction, and the facet angle is almost 55 degree. So I get confused... ------------------ Best regards, Xing Sheng 2012-03-01 From: Roger Shile Date: 2012-03-01 15:49 To: General MEMS discussion Subject: Re: [mems-talk] silicon KOH etch Any shape of mask opening will eventually etch to a pyramidal pit bounded by 111 planes. The orientation of this pit is fixed. The size is determined by the extent of the mask opening in the 110 directions. A square opening with side length d aligned to the 100 direction will result in a pyramidal pit with a base dimension d*sqrt2. (a square circumscribed on the original square at 45 degrees). Roger Shile From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Xing Sheng Sent: Wednesday, February 29, 2012 3:20 PM To: mems-talk Subject: [mems-talk] silicon KOH etch Hi, I have a question about 100 silicon wafer KOH anisotropic etch. I opened a square window on 100 silicon using SiN as protection. Normally the window should be aligned along 110 direction, so that we can get inverted pyramid structure, and the plane angle is 55 degree. However, I opened the window along 100 direction. It seems similar pyramid is obtained. This is weird. What is the plane direction I got, and what is the side wall angle at this time? Thanks! ------------------ Best regards, Xing Sheng 2012-02-29 _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk