<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.EmailStyle18
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-AU" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Hi Scott,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Usually the solution you mentioned should be able to etch the material. You may consider using smaller amount of water.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Do you have any other layers on top of the InGaAlAs layer?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Note H2O2 solutions should be made fresh every time of usage.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">I used a same solution to etch GaAs/AlAs at RT. Also we did sometime at 0°C.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">CH4/H2 process will etch very slowly Al containing materials.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Hope this helps,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Fouad Karouta<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">*************************************<o:p></o:p></p>
<p class="MsoNormal">Manager ANFF ACT Node<o:p></o:p></p>
<p class="MsoNormal">Australian National Fabrication Facility<o:p></o:p></p>
<p class="MsoNormal">Research School of Physics<o:p></o:p></p>
<p class="MsoNormal">L. Huxley Building (#56), Mills Road, Room 4.02<o:p></o:p></p>
<p class="MsoNormal">Australian National University<o:p></o:p></p>
<p class="MsoNormal">ACT 2601, Canberra, Australia<o:p></o:p></p>
<p class="MsoNormal">Tel: + 61 2 6125 7174<o:p></o:p></p>
<p class="MsoNormal">Mob: + 61 451 046 412<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Email: <a href="mailto:fouad.karouta@anu.edu.au">
<span style="color:blue">fouad.karouta@anu.edu.au</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><a href="http://anff-act.anu.edu.au/"><span style="color:blue">http://anff-act.anu.edu.au/</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> labnetwork-bounces@mtl.mit.edu <labnetwork-bounces@mtl.mit.edu>
<b>On Behalf Of </b>McWilliams, Scott<br>
<b>Sent:</b> Wednesday, 8 January 2020 7:32 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] wet etching InGaAlAs<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">Hello All, <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I’m processing some wafers and need to wet etch layers of InGaAlAs of various compositions (Al</span><span lang="EN-US" style="font-size:8.0pt">x
</span><span lang="EN-US">values of x = 0.48 to 0.27). I pulled a reference from the A.W. Clawson III-V etch reference guide that H3PO4/H202/H20 1:1:10 should etch this material, but it is not etching. The referenced paper does not provide the etchant temperature.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I suspect that I need to perform a surface etch of some type before etching the InGaAlAs. We do have the limitation that our current mask is 600 angstroms of silicon nitride, so we may be prohibited from performing HF
containing surface etches.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Does anyone have experience with this material and a recommended surface clean? Is there a better etchant to use? Has anyone attempted to dry etch this material with a CH4/H2 process?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Thank you, Scott<o:p></o:p></span></p>
</div>
</body>
</html>