Dear Ken, I will be so grateful if you send these list. I think it is a glass layer, because the wafer was immersed for along time but no more etching was showing up, do you have any idea about how can we remove such glass because BOE it didn't remove this layer, either. and one more thing just for curiosity, does re-oxidize SOI wafer affect the structure of the wafer, do you think re-oxidation ( thermal wet oxidation) might be reason to grow such layer, ( the temperature for oxidation that we use is around 650C for 4 hour), is there specific procedures to oxidize SOI wafer. best regards BigBangwidth the exabit netOpticalTM company Abdullah Tashtoush MEMS Process Engineer Tel: (780) 490-4800 Ext. (227) Cell:(780) 953-0702 Fax: (780) 430-8545 atashtoush@BigBangwidth.com www.BigBangwidth.com -----Original Message----- From: Kenneth Smith [mailto:kasmith2@ix.netcom.com] Sent: Tuesday, July 31, 2001 6:16 PM To: Abdullah Tashtoush Subject: Re: [mems-talk] (no subject) Dear Abdullah, Should you have a need for Si Wafers or want to review my Excess SOI (BESOI) prime wafer listing, let me know. Regards, Ken Smith > Abdullah Tashtoush wrote: > > Dear MEMS research, > when TMAH or EDP used as an etchant, and SOI 40 um wafer was used, I > figured out that the etch stop and it didn't hit the buried Silicon > dioxide and a layer with thickness based up on SEM photo ~10-15um, do > you have any idea about this issue , if so would you please tell me > what this layer is, and how can we get rid of it, and really I > appreciate if you tell me about the reason that causes this layer. > thanks a lot. > > BigBangwidth > the exabit netOpticalTM company > > Abdullah Tashtoush > MEMS Process Engineer > Tel: (780) 490-4800 Ext. (227) > Cell:(780) 953-0702 > Fax: (780) 430-8545 > atashtoush@BigBangwidth.com > www.BigBangwidth.com > > -- Ken Smith Kmbh Associates 4968 Charter Road Rocklin, CA 95765 USA 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. Service in SOI, Polishing SSP and DSP.