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We also use TDMAH in our Fiji at UF with no issues. Very reliable
end of life and performance.<br>
<br>
I too would like to be added to an ALD mail group if possible.<br>
<br>
Thank you,<br>
Brent
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<div class="moz-cite-prefix">On 8/19/2026 12:10 PM, Frank Flack
wrote:<br>
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<blockquote type="cite" cite="mid:SJ0PR06MB7034355ECC354D651681D8C9D8A52@SJ0PR06MB7034.namprd06.prod.outlook.com">
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<div><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#FA4616"><b>[External
Email]</b></span>
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Hi all,</div>
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We use TDMAH in our Fiji G2 and have not had delivery issues
though we do keep the cylinder at elevated temps when idle.</div>
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<br>
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Is there a separate ALD group mail or just an informal mailing
list? Please add me, if so!</div>
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<br>
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Thanks,</div>
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Frank</div>
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<br>
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<p class="elementToProof" style="margin-top: 0px; margin-bottom: 0px; font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">
<span style="color: rgb(0, 0, 0);">Frank S. Flack</span></p>
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<span style="color: rgb(0, 0, 0);">University of Wisconsin
Centers for Nanoscale Technology</span></p>
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<span style="color: rgb(0, 0, 0);">Rm. 3120 Engineering
Centers Bldg.</span></p>
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<span style="color: rgb(0, 0, 0);">1550 Engineering Drive</span></p>
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<span style="color: rgb(0, 0, 0);">Madison, WI 53706</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> labnetwork
<a class="moz-txt-link-rfc2396E" href="mailto:labnetwork-bounces@mtl.mit.edu"><labnetwork-bounces@mtl.mit.edu></a> on behalf of Martin,
Michael <a class="moz-txt-link-rfc2396E" href="mailto:michael.martin@louisville.edu"><michael.martin@louisville.edu></a><br>
<b>Sent:</b> Tuesday, August 18, 2026 4:35 PM<br>
<b>To:</b> Network Fab <a class="moz-txt-link-rfc2396E" href="mailto:labnetwork@mtl.mit.edu"><labnetwork@mtl.mit.edu></a><br>
<b>Cc:</b> Stefan Myhajlenko <a class="moz-txt-link-rfc2396E" href="mailto:myhajlenko@asu.edu"><myhajlenko@asu.edu></a>;
dleber <a class="moz-txt-link-rfc2396E" href="mailto:dleber@vt.edu"><dleber@vt.edu></a>; Yu <a class="moz-txt-link-rfc2396E" href="mailto:ywu387@gatech.edu"><ywu387@gatech.edu></a>;
a-dhote <a class="moz-txt-link-rfc2396E" href="mailto:a-dhote@northwestern.edu"><a-dhote@northwestern.edu></a>; Chen, Zhi D.
<a class="moz-txt-link-rfc2396E" href="mailto:zhi.chen@uky.edu"><zhi.chen@uky.edu></a>; Gary
<a class="moz-txt-link-rfc2396E" href="mailto:gary.spinner@ien.gatech.edu"><gary.spinner@ien.gatech.edu></a>; Bill Mitchell
<a class="moz-txt-link-rfc2396E" href="mailto:mitchell@ece.ucsb.edu"><mitchell@ece.ucsb.edu></a>; Morris, JD
<a class="moz-txt-link-rfc2396E" href="mailto:james.morris.3@louisville.edu"><james.morris.3@louisville.edu></a>; Tony Whipple
<a class="moz-txt-link-rfc2396E" href="mailto:whipp003@umn.edu"><whipp003@umn.edu></a><br>
<b>Subject:</b> [labnetwork] Some info on HfO2 precursors</font>
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Hi Labnetwork: </div>
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I wanted to summarize some advice from our informal ALD
working group (formerly NNCI ALD group I think) about HfO2
precursors so that this info will be in the labnet archive
and available in the Labnetwork chatbot. </div>
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<br>
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"I see there are something like 4 Hf precursors that folks
have used in the literature. </div>
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<br>
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TEMAHf
(Tetrakis(ethylmethylamido)hafnium(IV),(EtMeN)4Hf) </div>
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Tris(dimethylamido)cyclopentadienyl Hafnium, HfCp(NMe2)3
(HyALD)</div>
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Tetrakis(dimethylamido)hafnium(IV) [TDMAH]</div>
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And a chlorinated Hf compound. </div>
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<br>
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We have some limited experience with TDMAH but Beneq
suggests TEMAHf or HyALD is more stable. What is your go-to
Hf precursor? " </div>
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Tony Whiple from Minnesota pointed out that they:</div>
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"use Tetrakis(dimethylamido)hafnium(IV) [TDMAH] in all of
our ALD systems, Savannah, Lesker, Fiji. We continue to keep
with the same precursors as users have set processes for
that. </div>
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<br>
We have had a few issues with using this, mainly the random
end of service of the precursor.<br>
The causes of the cylinder going bad ( not able to pulse
material, while the cylinder is only half empty ) can at
times be assigned to the cylinder heat being turned off and
going to room temperature. After reheating to the correct
temperature, there is a chance the cylinder will go bad. We
have had this happen only a few times. To keep this from
happening, we avoid having the cylinders cool off." </div>
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Evidently others (Mac from Harvard and Bangzhi from PSU)
have had similar problems with TDMAH- incidentally this is a
big problem with the SnO2 precursor TDMASn. Mac suggests
loading only a small amount of TDMAH at a time, and Bangzhi
suggested that sometimes cycling the manual valve to the
bottle may free up the delivery line. </div>
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My inclination based on this advice is to try the <span style="color:rgb(0,0,0)">
TEMAHf
(Tetrakis(ethylmethylamido)hafnium(IV),(EtMeN)4Hf) option
given that we may not have super high throughput so a
stable precursor might be important in our case and Beneq
has provided a starting recipe. Generally, my impression
is that the chlorinated precursors can cause problems with
the plumbing and pumps since the reaction yields HCl . </span></div>
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I'd love to hear any other advice people may want to share
on this process and precursors. </div>
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<p style="direction:ltr; margin-top:0px; margin-bottom:0px"><span style="font-family:Calibri,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">Regards,</span></p>
<p style="direction:ltr; margin-top:0px; margin-bottom:0px"><span style="font-family:Calibri,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
Michael Martin, Ph.D.</span></p>
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<p style="direction:ltr; margin-top:0px; margin-bottom:0px">Manager,
<span style="font-family:Calibri,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">
Micro/Nano Technology Center</span></p>
<p style="direction:ltr; margin-top:0px; margin-bottom:0px"><span style="font-family:Calibri,Helvetica,sans-serif; font-size:12pt; color:rgb(0,0,0)">University
of Louisville</span></p>
<div style="direction:ltr; font-family:Calibri,sans-serif; font-size:11pt; color:rgb(0,0,0)">
(502) 552-1945</div>
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