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<br><br><div class="gmail_quote">On Fri, Jul 27, 2012 at 12:58 PM, Warren Lai <span dir="ltr"><<a href="mailto:warren.lai@rutgers.edu" target="_blank">warren.lai@rutgers.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div link="blue" vlink="purple" lang="EN-US"><div><p class="MsoNormal">Colleagues<u></u><u></u></p><p class="MsoNormal">
<u></u> <u></u></p><p class="MsoNormal">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:<u></u><u></u></p>
<p><u></u><span>1.<span style="font:7pt "Times New Roman""> </span></span><u></u>If there is cross-contamination issue for MOS users?<u></u><u></u></p><p><u></u><span>2.<span style="font:7pt "Times New Roman""> </span></span><u></u>Any procedure to minimize the contamination (Additional pre-clean or post-clean? Certain deposition to “bury” the contamination etc.)?<u></u><u></u></p>
<p class="MsoNormal">Several things to note are:<u></u><u></u></p><p><u></u><span>a.<span style="font:7pt "Times New Roman""> </span></span><u></u>The exposed areas are <span style="color:rgb(31,73,125)">sapphire, </span>Bi2Se3 and Nb<u></u><u></u></p>
<p><u></u><span>b.<span style="font:7pt "Times New Roman""> </span></span><u></u>The device is made by MBE and ion-milling, so the device (and exposed area of Bi2Se3 and Nb) is quite small<u></u><u></u></p>
<p><u></u><span>c.<span style="font:7pt "Times New Roman""> </span></span><u></u>Because of MBE, the Bi2Se3 is quality grade and “clean”<u></u><u></u></p><p><u></u><span>d.<span style="font:7pt "Times New Roman""> </span></span><u></u>They prefer pre-clean with only acetone and IPA (based on some limited experience of acid damage to the device)<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">Your advice will be most appreciated.<u></u><u></u></p><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal">Best regards,<u></u><u></u></p><p class="MsoNormal">
<u></u> <u></u></p><p class="MsoNormal">Warren Lai, Ph.D.<u></u><u></u></p><p class="MsoNormal">Associate Director<u></u><u></u></p><p class="MsoNormal">Micro Electronics Research Laboratory (MERL)<u></u><u></u></p><p class="MsoNormal">
Electrical and Computer Engineering Department<u></u><u></u></p><p class="MsoNormal">Rutgers, The State University of New Jersey<u></u><u></u></p><p class="MsoNormal">Room EE-115<u></u><u></u></p><p class="MsoNormal">94 Brett Road, Piscataway, NJ 08854<u></u><u></u></p>
<p class="MsoNormal"><a href="tel:732-445-0680" value="+17324450680" target="_blank">732-445-0680</a><u></u><u></u></p><p class="MsoNormal"><a href="mailto:warren.lai@rutgers.edu" target="_blank">warren.lai@rutgers.edu</a><u></u><u></u></p>
<p class="MsoNormal"><a href="http://www.merl.rutgers.edu" target="_blank">www.merl.rutgers.edu</a><u></u><u></u></p><p class="MsoNormal"><a href="http://www.ece.rutgers.edu" target="_blank">www.ece.rutgers.edu</a><u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p></div></div><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><br>
<br></blockquote></div><br>