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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>John<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thank you for sharing the details, so we can make an informed decision. Most appreciated.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Best,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Warren<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Warren Lai, Associate Director, MERL, ECE, Rutgers<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>EE-115 <a href="mailto:warren.lai@rutgers.edu"><span style='color:blue'>warren.lai@rutgers.edu</span></a> 732-445-0680 www.merl.rutgers.edu<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> J Provine [mailto:jprovine@stanford.edu] <br><b>Sent:</b> Saturday, July 28, 2012 5:05 PM<br><b>To:</b> warren.lai@rutgers.edu<br><b>Cc:</b> labnetwork@mtl.mit.edu<br><b>Subject:</b> Re: [labnetwork] ALD cross contamination issue<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>hi warren,<br>i would think this is a cross-contamination issue for MOS users because of the Bi2Se3. the Nb and sapphire, are not a concern. if you really want to do this, i think you need to eliminate physical contact (tweezers, sliding on the heater of the chamber, etc. luckily ald is relatively low in temperature and you can paste the chamber after the run. i'm assuming this is a savannah ald tool. some recommendations:<br>1) have them keep their pieces on a clean Si or oxidized Si carrier wafer. <br>2) the tweezers that go into chamber and touch the Si carrier wafer should not be the tweezers touching the contaminated sample<br>3) after deposition run 200 cycles of alumina on an empty chamber to coat everything down with 20nm of film (user should book this time as well). <br>4) (optional) to really be careful, you could make a MOSCAP before and after the above three steps and compare performance. if the chamber was contaminated (as shown by CV degradation) you could put the user on the hook cleaning the chamber - which would cause a few days to a week of downtime. but if everything is great, then the above can be the procedure going forward. <br><br>we follow steps 1-3 for a GaAs and InGaAs samples because we found through 4 that it isn't leave a lasting issue.<br><br>hope this helps.<br>j<o:p></o:p></p><div><p class=MsoNormal>On Fri, Jul 27, 2012 at 12:58 PM, Warren Lai <<a href="mailto:warren.lai@rutgers.edu" target="_blank">warren.lai@rutgers.edu</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Colleagues<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>I have a cross contamination question on our Cambridge ALD tool. A user requests to do Al2O3 on Bi2Se3 and Nb structures on sapphire (and prefers to use only acetone and IPA pre-clean). Does anyone know:<o:p></o:p></p><p>1.<span style='font-size:7.0pt'> </span>If there is cross-contamination issue for MOS users?<o:p></o:p></p><p>2.<span style='font-size:7.0pt'> </span>Any procedure to minimize the contamination (Additional pre-clean or post-clean? Certain deposition to “bury” the contamination etc.)?<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Several things to note are:<o:p></o:p></p><p>a.<span style='font-size:7.0pt'> </span>The exposed areas are <span style='color:#1F497D'>sapphire, </span>Bi2Se3 and Nb<o:p></o:p></p><p>b.<span style='font-size:7.0pt'> </span>The device is made by MBE and ion-milling, so the device (and exposed area of Bi2Se3 and Nb) is quite small<o:p></o:p></p><p>c.<span style='font-size:7.0pt'> </span>Because of MBE, the Bi2Se3 is quality grade and “clean”<o:p></o:p></p><p>d.<span style='font-size:7.0pt'> </span>They prefer pre-clean with only acetone and IPA (based on some limited experience of acid damage to the device)<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Your advice will be most appreciated.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Best regards,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Warren Lai, Ph.D.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Associate Director<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Micro Electronics Research Laboratory (MERL)<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Electrical and Computer Engineering Department<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Rutgers, The State University of New Jersey<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Room EE-115<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>94 Brett Road, Piscataway, NJ 08854<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="tel:732-445-0680" target="_blank">732-445-0680</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="mailto:warren.lai@rutgers.edu" target="_blank">warren.lai@rutgers.edu</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="http://www.merl.rutgers.edu" target="_blank">www.merl.rutgers.edu</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="http://www.ece.rutgers.edu" target="_blank">www.ece.rutgers.edu</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div></div><p class=MsoNormal style='margin-bottom:12.0pt'><br>_______________________________________________<br>labnetwork mailing list<br><a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br><a href="https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork" target="_blank">https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a><o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>