From conrad at Princeton.EDU Mon Jun 1 15:58:41 2009 From: conrad at Princeton.EDU (Conrad Silvestre) Date: Mon, 1 Jun 2009 15:58:41 -0400 Subject: [labnetwork] Quartz Tube Ground Joint End Caps Message-ID: <6B9CB57AADA34DC0BE5D7896C00142CF@princeton.edu> Does anyone know of any difficulties with using ground joint end caps on quartz tubes that have a side port for venting gases? The tubes will run up to 1150C. How much is differential thermal expansion a problem resulting in the end caps getting stuck? Conrad Silvestre Department of Electrical Engineering C402 EQuad, CN-5263 Princeton University Princeton, New Jersey 08544-5263 Office: 609-258-6236 Lab: 609-258-6234 FAX: 609-258-1840 Business Cell: 609-356-8825 -------------- next part -------------- An HTML attachment was scrubbed... URL: From bradshaw at utdallas.edu Fri Jun 19 13:30:26 2009 From: bradshaw at utdallas.edu (Keith Bradshaw) Date: Fri, 19 Jun 2009 12:30:26 -0500 Subject: [labnetwork] Cadmium Telluride sputtering target exchange problems Message-ID: We are getting a strong smell from the chamber and instant oxidation and flaking of product deposited on the chimney of our Sputtering system when changing the Cad-Tel target. What is done to avoid this? Is this smell harmful? The flakes are very dark and seem to form when we open the system up to atmosphere. It is load locked so normally it doesn't see air. Keith Bradshaw 972-883-2099 RL 10 University of Texas at Dallas Clean Room NSERL building -------------- next part -------------- An HTML attachment was scrubbed... URL: From pkarulkar9 at gmail.com Sun Jun 21 16:41:54 2009 From: pkarulkar9 at gmail.com (Pramod Karulkar) Date: Sun, 21 Jun 2009 12:41:54 -0800 Subject: [labnetwork] Cadmium Telluride sputtering target exchange problems In-Reply-To: References: Message-ID: <4A3E9B12.9080504@gmail.com> Explosive oxidation of very pure thin films in a vacuum chamber is known. Popping sounds can be heard if a chamber used for depositing titanium or aluminum is suddenly exposed to room air. Flash of light can also be seen if the chamber is full of dust or peeling matter. Both can be dangerous. You have to set up protocols for slow venting, waiting for a long time ( hour or hours) to allow for slow passivation of unoxidized materials, and then opening the chamber. Vent and pump cycles may help too. Check with your vendor. Slow venting may reduce peeling and release of particles. You have to allow the whole system to reach room temperature (or slightly above RT) before venting it. However, some peeling of material will occur and the chimney and chamber walls/parts will have to be cleaned thoroughly using a dedicated vacuum cleaner. Again protocols for this will have to be set up. You may follow processes/precautions used to clean similar equipment such as CVD chambers or ion implant source chambers. Color of the flakes depends on the composition and surface finish. "Black" may not mean anything. It may be an off stoichiometric deposition with residual gas contamination that may vary with position in the chamber. Smells are hard to track down unless you sample the gas and analyze. Complex species are formed if you are doing anything reactive in the chamber. Smells can arise from back streaming of some vapors from a pumping station. Check with the vendor. Repeated cycles of venting and rough pump down without opening the door will help to reduce the concentration of smelly components. (Plasma etch chambers tend to have unusual odors. Well exhausted bench, hood, enclosure etc has to be used to clean such chambers. A mask is needed to.) Vendor websites used to have info on such topics. If you did not download and save it, most of it is gone because of the newer style of websites. http://www.asm.com/index.php?option=com_content&task=view&id=51&Itemid=67 Hope this helps. Pramod C Karulkar Fairbanks Alaska 907 457 4123 443 622 4425 Keith Bradshaw wrote: > > We are getting a strong smell from the chamber and instant oxidation > and flaking of product deposited on the chimney of our Sputtering > system when changing the Cad-Tel target. > > > > What is done to avoid this? > > > > Is this smell harmful? > > > > The flakes are very dark and seem to form when we open the system up > to atmosphere. It is load locked so normally it doesn't see air. > > > > Keith Bradshaw > > 972-883-2099 > > RL 10 > > University of Texas at Dallas Clean Room > > NSERL building > > > > ------------------------------------------------------------------------ > > _______________________________________________ > labnetwork mailing list > labnetwork at mtl.mit.edu > https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork > -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: pkarulkar9.vcf Type: text/x-vcard Size: 197 bytes Desc: not available URL: From rdutton at stanford.edu Sun Jun 21 17:07:55 2009 From: rdutton at stanford.edu (Bob Dutton) Date: Sun, 21 Jun 2009 14:07:55 -0700 Subject: [labnetwork] Cadmium Telluride sputtering target exchange problems In-Reply-To: References: Message-ID: <4A3EA12B.8080804@stanford.edu> Keith Bradshaw wrote: > > We are getting a strong smell from the chamber and instant oxidation > and flaking of product deposited on the chimney of our Sputtering > system when changing the Cad-Tel target. > > What is done to avoid this? > > Is this smell harmful? > > The flakes are very dark and seem to form when we open the system up > to atmosphere. It is load locked so normally it doesn?t see air. > > Keith Bradshaw > > 972-883-2099 > > RL 10 > > University of Texas at Dallas Clean Room > > NSERL building > > ------------------------------------------------------------------------ > > _______________________________________________ > labnetwork mailing list > labnetwork at mtl.mit.edu > https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork > Both Cadmium and Telurium are not good things! Te can have a smell like garlic (probably one of the trace elements in garlic anyway). Cadmium was outlawed many years ago as a car-bumper coating, again due to toxic properties... I hope you folks have studied the safety books! Bob Dutton Stanford U. From bob at eecs.berkeley.edu Sun Jun 21 20:05:41 2009 From: bob at eecs.berkeley.edu (Bob Hamilton) Date: Sun, 21 Jun 2009 17:05:41 -0700 Subject: [labnetwork] Cadmium Telluride sputtering In-Reply-To: <4A3EA12B.8080804@stanford.edu> References: <4A3EA12B.8080804@stanford.edu> Message-ID: I suggest a review of the issue of tellurium breath, which can occur at relatively low Te exposure rates: http://en.wikipedia.org/wiki/Tellurium You should use dedicated chamber hardware when sputtering CdTe. At the UC Berkeley Microlab we often invoke disposable shielding (aluminum foil) to contain deposit residues and dispose of the such shielding through our campus hazardous waste agents. In addition, we fabricate dedicated chamber hardware such as the target clamp rings, screws and substrate holders. These can then be sent, as necessary to chemical cleaning companies who specializes in semiconductor parts cleaning such as TMPI in Hayward, CA. Firms such as TMPI are trained and licensed to clean chamber hardware and are qualified and used to working with toxic metals. With proper caution and engineering solutions toxic metals can be handled safely. Bob Hamilton Robert Hamilton University of California at Berkeley Microlab Facilities Manager Rm406 Cory Hall Berkeley, CA 94720-1770 510-642-2716 510-642-2916 (Fax) 510-325-7557 (Cell) bob at silicon2.eecs.berkeley.edu -----Original Message----- From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Bob Dutton Sent: Sunday, June 21, 2009 2:08 PM To: Keith Bradshaw Cc: labnetwork at mtl.mit.edu; Duenes, Arnold; 'Roger Robbins' Subject: Re: [labnetwork] Cadmium Telluride sputtering target exchange problems Keith Bradshaw wrote: > > We are getting a strong smell from the chamber and instant oxidation > and flaking of product deposited on the chimney of our Sputtering > system when changing the Cad-Tel target. > > What is done to avoid this? > > Is this smell harmful? > > The flakes are very dark and seem to form when we open the system up > to atmosphere. It is load locked so normally it doesn't see air. > > Keith Bradshaw > > 972-883-2099 > > RL 10 > > University of Texas at Dallas Clean Room > > NSERL building > > ---------------------------------------------------------------------- -- > > _______________________________________________ > labnetwork mailing list > labnetwork at mtl.mit.edu > https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork > Both Cadmium and Telurium are not good things! Te can have a smell like garlic (probably one of the trace elements in garlic anyway). Cadmium was outlawed many years ago as a car-bumper coating, again due to toxic properties... I hope you folks have studied the safety books! Bob Dutton Stanford U. _______________________________________________ labnetwork mailing list labnetwork at mtl.mit.edu https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork From Zhang.Bin at mtpvcorp.com Sun Jun 21 23:18:35 2009 From: Zhang.Bin at mtpvcorp.com (Ben) Date: Sun, 21 Jun 2009 23:18:35 -0400 Subject: [labnetwork] how to reduce the contact resistance of metal-germanium? Message-ID: <001901c9f2e8$215eb880$641c2980$@Bin@mtpvcorp.com> Hello all, I?m in a project of building electronic device on bulk germanium wafer, and find out the contact resistance become a limitation of the performance. Because the band pining of germanium-metal interface especially the N-type germanium, the resistance is hard to be reduced with the high Schottky barrier. One way is to use highly dosed germanium but it seem there is limitation to increase the electron activated concentration for germanium. Is there any good way to reduce the contact resistance? Thank you Regards Ben Boston University Phone: 857-366-2675 Address? 8 ST.Mary?s street Room 609 Boston, MA 02215 -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Bin Zhang.vcf Type: application/octet-stream Size: 4495 bytes Desc: not available URL: From jrweaver at purdue.edu Mon Jun 22 16:51:01 2009 From: jrweaver at purdue.edu (Weaver, John R) Date: Mon, 22 Jun 2009 16:51:01 -0400 Subject: [labnetwork] PMS 7640 Condensation Particle Counter manual Message-ID: I just acquired a PMS 7640 Condensation Particle Counter without the manual. Does anyone have a copy of the manual that they could provide by pdf? Also, it is missing its butadiene canister. I am hoping that is described in the manual, if not, does anyone know what it looks like? Thanks, John John R. Weaver Facility Manager Birck Nanotechnology Center Purdue University (765) 494-5494 jrweaver at purdue.edu -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image001.gif Type: image/gif Size: 70 bytes Desc: image001.gif URL: