Final note here- Westinghouse does not produce FZ Silicon anymore either since early 90s. So likely it is >15,000 or more like >12,000 ohm-cm unless you want just a few slices then there are likely some from first 2 cm of the growth >20,000 ohm-cm if luckily. Good luck in the search and should you find a source let us know. Regards, Ken Michael Bragger wrote: > Fred, > > I guess I need to weigh in here. The intrinsic resistivity of silicon is 240 > kOhm-cm as indicated on the tydex web site. This is the theoretical limit. > It also mentions that 30 kOhm-cm is available. Generally, this is about the > best you are going to get. Anything that you do to this material will reduce > the resistivity, period. The degree to which you are careful will determine > how much the resistivity will be reduced. The highest resistivity material > that I have ever seen was 100 kOhm-cm, which was probably close to a world > record. I was able to get a 3-inch diameter boule of this material from > Westinghouse in the early 90's. Unfortunately, they did not and do not sell > silicon commercially and my contacts are no longer there. > > Good luck, > > Mike Barger > Klesis Corporation > > > -----Original Message----- > From: mems-talk-admin@memsnet.org [mailto:mems-talk-admin@memsnet.org]On > Behalf Of David Nemeth > Sent: Monday, May 20, 2002 11:44 AM > To: mems-talk@memsnet.org > Subject: RE: [mems-talk] Highest resistivity silicon? > > > First, 250 K-Ohm cm seems like an unrealistically high value. I've seen > silicon up to 12 KOhm-cm, and have used material up to 6KOhm-cm. Looking at > the web site, they don't actually seem to produce this value - it might just > be the theoretical resistivity of pure silicon with no dopants that they are > quoting. > > There are other suppliers of high-resistivity silicon, for example wacker > and topsil. > > Next, I've heard (but can't say for sure) that if you grow a thermal oxide, > the resistivity will never be higher than a few thousand ohm-cm when your > done, no matter how good it was to start. Any thermal treatment will > diffuse some impurities into the wafer, depending on the time and > temperature of the treatment. > > If you need to end up with 2000 ohm-cm, your probably fine. If you need to > end up with 6000 ohm-cm, you will need to be careful about your thermal > processing and may have problems. If you need 250000 ohm-cm, your probably > out of luck. > > > David Nemeth > Senior Process Engineer > Sophia Wireless, Inc. > 14225-C Sullyfield Circle > Chantilly, VA > Ph: (703) 961-9573 x206 > Fax:(703) 961-9576 > > -----Original Message----- > From: mems-talk-admin@memsnet.org [mailto:mems-talk-admin@memsnet.org]On > Behalf Of Fred Hussain > Sent: Monday, May 20, 2002 6:47 AM > To: mems-talk@memsnet.org > Subject: [mems-talk] Highest resistivity silicon? > > > Dear all, > > I am looking for silicon substrates which can be machined using conventional > MEMS type processes, but at the same time are highly insulating. I've found > a web page with silicon of 250Kohm-cm resistivity - > http://www.tydex.ru/materials/materials2/Si.html. > > Does anybody: > have any experience of working with such materials? > know of any issues, for example the stability of the resistivity with > temperature? > micromachined it without any major issues? > know of any suppliers? > > Thanking you in advance. > > Regards, > > Fred. > > -------------------------------------------- > Dr Fred Hussain > The Technology Partnership plc > Melbourn Science Park > Cambridge Road > Melbourn > Royston > Hertfordshire > SG8 6EE > > Tel: 01763 262626 > Fax: 01763 261582 > www.ttpgroup.com > --------------------------------------------- > _______________________________________________ > mems-talk@memsnet.org mailing list: to unsubscribe or change your list > options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk > Hosted by the MEMS Exchange, providers of MEMS processing services. > Visit us at http://www.mems-exchange.org/ > _______________________________________________ > mems-talk@memsnet.org mailing list: to unsubscribe or change your list > options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk > Hosted by the MEMS Exchange, providers of MEMS processing services. > Visit us at http://www.mems-exchange.org/ > _______________________________________________ > mems-talk@memsnet.org mailing list: to unsubscribe or change your list > options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk > Hosted by the MEMS Exchange, providers of MEMS processing services. > Visit us at http://www.mems-exchange.org/ > > -- Kmbh Associates 47 Rocket Circle Rancho Cordova, CA 95742 U S A 510-714-5055 Efax- 510 217 4421 or 561 658 6136 High Purity Float Zone and Specialty CZ Silicon for Power, IR and Mirror Optics, Optoelectronics, MEMS, SOI, and other Semiconductor applications. 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