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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"'>Hi<span style='color:#1F497D'> </span>Chandrashekar<span style='color:#1F497D'>, </span>At first it seems that your raise #2 power is just too high but many other factors may be in play. Hopefully your system has a sweep controller which you should be using to set the Electron Beam Pattern to sweep the surface of the melt. This is the best way to distribute the heat across the entire melt. Focusing the beam in one <u>stationary</u> spot in the center will cause exactly the problems that you are describing and could lead to a damaged liner or hearth. If you have no sweep available, you may try extending your rise times to more slowly heat the material. Any time that you heat too fast or have to shut off the beam instantly (like when the melt is spitting all over) you run the risk of cracking the liner from thermal shock. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Also, you should run the system manually first and watch carefully what happens and at what power levels. If your shutter does not have a chimney or hole that allows the rate sensor to see the melt at all times, you will need to do the testing with the shutter open and record what power levels it takes to achieve a given deposition rate. This way you can set the rise and soak programs to safe levels and when your shutter opens it will already be at the desired deposition rate. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>If the crucible liner disintegrates and leaves pieces in the melt, we replace the liner and the melt since it is likely contaminated and nickel is one of the cheaper materials to purchase.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Hope this helps,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal>Mark Heiden <br>UC Riverside <br>Center for Nanoscale Science and Engineering <br>NanoFab Cleanroom Manager <br>(951) 827-2551 <br>mheiden@engr.ucr.edu <span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><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"'> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu] <b>On Behalf Of </b>Chandrashekar S Kambar<br><b>Sent:</b> Wednesday, July 31, 2013 5:13 AM<br><b>To:</b> labnetwork@mtl.mit.edu<br><b>Subject:</b> [labnetwork] E-Beam Evaporation, Ni optimization.<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p>Hi,<br> <br>We are trying to optimize Ni with E-Beam Evaporator (TECPORT). <br> <br>The E-Beam power is raised in two steps: RAISE 1, SOAK 1 AND RAISE 2, SOAK 2.<br>ELECTRON BEAM PATTERN: Focused to one point (to the middle of the crucible).<br>CRUCIBLE: Graphite.<br> <br>ISSUE: During the RAISE 1, everything seems to be normal and only the material in the middle of the crucible gets melted. During the RAISE 2 the material starts to spit out of the crucible. During the deposition the spitting increases drastically, thus we will be forced to stop the deposition. After the deposition when we take out the crucible, crucible was broken across the wall. However there was no damage done to the pocket holder (Hearth). <br> <br>Power % : Raise 1: 5% (V= 6.99 KV and I ~ 70 mA)<br> Raise 2: 10% (V= 6.99 KV and I ~ 120 mA)<br> During the deposition Power % goes up to 16% and the current goes up to 180 mA ( V = 6.99 KV constant).<br> <br>We need to know, if there is any way to reduce the crucible cracking and to avoid the spitting of the material. <br> <br>QUESTION 2:<br> <br>During the deposition the crucibles are cracked and its pieces are stuck with the Ni material. Is there any way to recover the material by removing the graphite pieces?<o:p></o:p></p><p>Thanks and Regards,<br>Chandrashekar S Kambar.<o:p></o:p></p><div><div><p class=MsoNormal><br> <o:p></o:p></p></div></div></div></body></html>