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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Hi Mingwei,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">We have the similar setup here at Stanford, with Cl<sub>2</sub>, BCl<sub>3</sub> and HBr.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">This tool is primarily dedicated to III-V etching, as well as Poly-Si etching using HBr and Cl₂.<o:p></o:p></span></p>
<ol style="margin-top:0in" start="1" type="1">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">Yes, you can. HBr offers excellent selectivity with oxide which making it less ideal for breaking native oxide. HBr alone also has slower etch rates
compared to F or Cl<sub>2</sub> chemistries. However, adding Cl₂ to HBr during the breakthrough step can effectively break the oxide layer and increase the etch rate. You can switch to HBr alone in Over etch step to precisely land on SiO₂. (you can substitute
the Cl<sub>2 </sub>and HBr with C<sub>2</sub>F<sub>6</sub>/CF<sub>4</sub>/CHF<sub>3</sub> in the breakthrough step)<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">We routinely mix these chemistries, and both III-V and Si etching remain stable, provided chamber cleaning and seasoning are performed regularly.<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">Si byproducts are fairly volatile, but we clean the chamber with SF<sub>6</sub>/O<sub>2</sub> to manage the chamber effectively.<o:p></o:p></span></li></ol>
<p class="MsoNormal"><span style="font-size:11.0pt">Let me know if you have any questions.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Best,<o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><b><span style="font-family:"Calibri Light",sans-serif;color:#8C1515;border:none windowtext 1.0pt;padding:0in">Lavendra Mandyam</span></b><b><span style="font-family:"Calibri",sans-serif;color:#8C1515"><o:p></o:p></span></b></p>
<p class="MsoNormal" style="background:white"><b><i><span style="font-family:"Calibri",sans-serif;color:black;border:none windowtext 1.0pt;padding:0in">Process Engineer – Dry Etching</span></i></b><b><i><span style="font-family:"Calibri",sans-serif;border:none windowtext 1.0pt;padding:0in"><o:p></o:p></span></i></b></p>
<p class="MsoNormal" style="background:white"><span style="font-family:"Calibri",sans-serif;color:black;border:none windowtext 1.0pt;padding:0in">Stanford Nanofabrication Facility</span><span style="font-family:"Calibri",sans-serif;border:none windowtext 1.0pt;padding:0in"><o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-family:"Calibri",sans-serif;color:black;border:none windowtext 1.0pt;padding:0in">Paul G. Allen Building</span><span style="font-family:"Calibri",sans-serif;border:none windowtext 1.0pt;padding:0in"><o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-family:"Calibri",sans-serif;color:black;border:none windowtext 1.0pt;padding:0in">420 Via Palou Mall</span><span style="font-family:"Calibri",sans-serif;border:none windowtext 1.0pt;padding:0in"><o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-family:"Calibri",sans-serif;color:black;border:none windowtext 1.0pt;padding:0in">Stanford, CA 94305</span><span style="font-family:"Calibri",sans-serif;border:none windowtext 1.0pt;padding:0in"><o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-family:"Calibri",sans-serif;color:black;border:none windowtext 1.0pt;padding:0in">Phone: (650) 498-1304
</span><span style="font-family:"Calibri",sans-serif;border:none windowtext 1.0pt;padding:0in"><o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-family:"Calibri",sans-serif;color:#0F4761;border:none windowtext 1.0pt;padding:0in"><a href="https://snf.stanford.edu/"><span style="color:#0F4761">https://snf.stanford.edu/</span></a><o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><u><span style="font-family:"Calibri",sans-serif;color:#0F4761;border:none windowtext 1.0pt;padding:0in"><a href="mailto:lavendra@stanford.edu"><span style="color:#467886">lavendra@stanford.edu</span></a><o:p></o:p></span></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">---------- Forwarded message ---------<br>
From: <strong><span style="font-family:"Aptos",sans-serif">MINGWEI LIN</span></strong> < ><br>
Date: Tue, Aug 27, 2024 at 1:08<span style="font-family:"Arial",sans-serif"> </span>PM<br>
Subject: [labnetwork] HBr and Cl2 mixing gases<br>
To: <a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a> < ><o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="color:black">Hi, Everyone:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">We are going to purchase a new metal etcher with Cl-based and HBr gases. Can anyone share the experience of HBr and Cl-based mixing gases for the etcher?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">1. Can the HBr and Cl2 mixing gases be used together for the Si/Poly Si etch? If Cl2 was used first followed by HBr, would any cleaning be necessary in between?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">2. Does anyone know about any impact on III-V materials (GaN for example) etch or device performance if HBr and Cl2/BCl3 are used in the chamber?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">3. If there is cross contamination issue about the mixing gases, what about the cleaning criteria if we switch HBr and Cl-based gases back and forth? Any better way for the tool management?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">Thanks/regards, <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">MINGWEI LIN, PhD<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">Process Engineer<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">Nanoscale Fabrication Center<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">University of Wisconsin-Madison<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal">_______________________________________________<br>
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