[labnetwork] [Non-DoD Source] Re: question about Liner for Ni Ebeam Evaporation

Fri Dec 13 18:36:28 EST 2024

I generally avoid hitting the whole list with a response, but spacers have
been so wildly successful at UC Berkeley that I feel obligated to express
good confidence in the method:

The primary difficulty with most of the materials discussed in this thread
is that most 2.2cc crucibles have thin walls and do not take to thermal
shock very well. The crucible liner itself has low mass and often a low
thermal mass (Specific heat * mass). A molten metal drastically increases
the thermal mass of the liner wherever it has good contact. If you miss
with your e-beam you can easily hit the crucible liner wall directly, and
doing so will create a hot spot. Generating a hot spot while having your
crucible cooled on all sides will cause massive thermal gradients across
the crucible wherever you do *not* have conformal contact of metal inside
the crucible. If you have a cup-shaped crucible with a 300C+ thermal
gradient across a 1cm space, it's going to shatter from internal stress in
most ceramic materials. Often, it will shatter with enough force to eject
pieces from the pocket. That includes graphite, Al2O3, or most other
materials. Copper liners won't do that but they introduce other alloying
problems that can be a pain to deal with.

We use spacers in all of our evaporators at the UC Berkeley NanoLab.
Spacing your ceramic liner off the floor of your hearth or pocket allows
you to use smaller beam currents to get the same temperature (effectively,
evaporation dep rate). Removing the sidewall of the liner from cooling
contact ensures that the cooling contact to the liner is always on a
surface in good contact with molten thermal mass during operation, because
liquid metal pools at the bottom of the liner. *That outright prevents
almost all forms of cracking.* We routinely do nickel, titanium, aluminum,
iron, and many more in FABMATE coated graphite. (Fabmate is a silicon
coating that just keeps the graphite dust down dramatically). Anything
FABMATE can't handle (e.g., Silver, Gold due to various material
incompatibilities and "Wierd stuff" that can happen.) Tungsten usually can,
especially if you coat it in ZrO2. We've got a very healthy evaporation
usage in the lab, and I haven't had a graphite crucible shatter since 2014
when we implemented spacers.

One last note - 2.2 cc tools are incredibly sensitive to beam focus.
(Deformed e-beams can overheat the top edge of your liner and shatter it)
Almost all research labs will tolerate a level of buildup on your focus
pole pieces that is unhealthy for a 2.2cc e-beam tool. Removing and
cleaning those pieces every couple months helps a ton. Also making sure
that there's no dust that worked its way under the pole pieces and
air-gapping your magnetic fields.

Hope this helps.

-Ryan

On Fri, Dec 13, 2024 at 1:13 PM Martin, Michael <
michael.martin at louisville.edu> wrote:

> LOL, TY for that info Michael.  I guess that will be our new M.O. for
> aluminum then.
> ------------------------------
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Yakimov,
> Michael <myakimov at albany.edu>
> *Sent:* Thursday, December 12, 2024 8:28 PM
> *To:* labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
> *Subject:* Re: [labnetwork] [Non-DoD Source] Re: question about Liner for
> Ni Ebeam Evaporation
>
> You don't often get email from myakimov at albany.edu. Learn why this is
> important <https://aka.ms/LearnAboutSenderIdentification>
>
> *CAUTION:* This email originated from outside of our organization. Do not
> click links, open attachments, or respond unless you recognize the sender's
> email address and know the contents are safe.
> For whatever reason, Aluminum doesn't wet copper when molten in the
> hearth. Evaporation temperature is above Cu melting point, but still that's
> what I see.  There may still be some Cu diffusion -  but I saw no damage to
> hearth after a few  depositions (disclaimer - I am not a fan of direct
> loading)
> Also, I tried real hard - although nonintentionally and fortunately
> unsuccessfully! - to burn a hole in a copper hearth. It's much harder than
> you think, I could only put a small dent in there.   That is a *huge* chunk
> of highly heat conductive copper that is water-cooled from the back. Makes
> me really wonder if there is actually liquid Al(or Ni) in contact with the
> copper at any point in the process, or liquid from above comes into contact
> with Cu and crystallizes right there. Certainly direct load would require
> higher beam power because of those things, with all associated effects like
> more outgassing and sample heating.
> On a separate note, there was a similar discussion about Al a year or two
> ago. The best idea I saw is exactly opposite to direct load - it was about
> using graphite spacer under Fabmate crucible to prevent heat contact of
> crucible walls and Cu hearth. Intermetallic crucibles are a second option.
> Makes me wonder if spacer is worth trying with Ni.
>
> Just my $0.02
>
> Mike
>
> _______________________________________________
>
> Michael Yakimov
>
> Research scientist
>
> Department  of Nanoscale Science and Engineering
>
> University at Albany - State University of NY
>
>
>
> 253 Fuller rd.
>
> Albany NY 12203
>
>
>
> Phone: 518-437-8609 lab
>
> e-mail: myakimov at albany.edu
>
> ------------------------------
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Martin,
> Michael <michael.martin at louisville.edu>
> *Sent:* Thursday, December 12, 2024 12:41 PM
> *To:* EDWARDS, JASON R CTR USAF AFMC AFRL/RYDD <
> jason.edwards.30.ctr at us.af.mil>; Beaudoin, Mario <beaudoin at physics.ubc.ca>;
> Graham Gibson <gibsong at queensu.ca>; Owain Clark <odc1n08 at soton.ac.uk>;
> shokoofe haghighi <shokoofe_haghighi at yahoo.com>; labnetwork at mtl.mit.edu <
> labnetwork at mtl.mit.edu>
> *Subject:* Re: [labnetwork] [Non-DoD Source] Re: question about Liner for
> Ni Ebeam Evaporation
>
> Personally, I'm terrified that without a liner we will punch a hole in the
> pocket.  This would be catastrophic since then coolant would spray into the
> chamber just a couple of cm away from both high voltage and high current
> electrodes.
>
> Jason (and others who go liner-less), wouldn't you be concerned about
> alloying the target material to the copper liner, I guess not?  We have
> issues similar to Ni with aluminum.  Almost every liner material seems
> incompatible with Al in one way or another yet ebeam Al can be very low
> stress. BTW, I believe lesker suggests to use thermal evaporation for Al.
> However, if you just put the Al in the pocket without a liner I would
> expect a copper-aluminum alloy to form. Didn't Al-ebeam come up not so long
> ago in this group with several mentioning they put the material directly in
> the pocket?
> ------------------------------
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of EDWARDS,
> JASON R CTR USAF AFMC AFRL/RYDD <jason.edwards.30.ctr at us.af.mil>
> *Sent:* Thursday, December 12, 2024 6:57 AM
> *To:* Beaudoin, Mario <beaudoin at physics.ubc.ca>; Graham Gibson <
> gibsong at queensu.ca>; Owain Clark <odc1n08 at soton.ac.uk>; shokoofe haghighi
> <shokoofe_haghighi at yahoo.com>; labnetwork at mtl.mit.edu <
> labnetwork at mtl.mit.edu>
> *Subject:* Re: [labnetwork] [Non-DoD Source] Re: question about Liner for
> Ni Ebeam Evaporation
>
> You don't often get email from jason.edwards.30.ctr at us.af.mil. Learn why
> this is important <https://aka.ms/LearnAboutSenderIdentification>
>
> *CAUTION:* This email originated from outside of our organization. Do not
> click links, open attachments, or respond unless you recognize the sender's
> email address and know the contents are safe.
>
> We evaporate straight out of the pocket for most of our metals, it’s
> interesting to hear that this may not be standard procedure for most labs.
> Not to draw attention away from the original question in this thread but I
> would like to hear more about what benefits you are getting from using
> liners. Is it just for ease of swapping metals in the pockets? In the
> instance of a Cu liner for Ni are you able to make a proper melt slug with
> the Ni considering you are unable to get the beam too close to the Cu
> liner? Thanks in advance.
>
>
>
>
>
>
>
>
>
>
>
>
>
> *Jason Edwards*
>
> KBR  |  Clean Room Facilities Manager , Defense Systems Engineering
>
> 2241 Avionics Circle, Area B, Bldg.600|WPAFB, OH, 45433-7322 I
>
> Office: +1 937.713.8741  | Mobile: +1 937.524.7701
>
>
>
>          Jason.edwards.30.ctr at us.af.mil
>
>
>
> <https://www.facebook.com/pages/KBR-Inc/153705171306696>
> <https://twitter.com/KBRincorporated>
> <https://www.linkedin.com/company/kbr-inc>
> <https://instagram.com/kbr.inc>
>
>
>
>
>
>
>
>
>
>
>
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> *On Behalf Of *Beaudoin,
> Mario
> *Sent:* Wednesday, December 11, 2024 5:07 PM
> *To:* Graham Gibson <gibsong at queensu.ca>; Owain Clark <odc1n08 at soton.ac.uk>;
> shokoofe haghighi <shokoofe_haghighi at yahoo.com>; labnetwork at mtl.mit.edu
> *Subject:* [Non-DoD Source] Re: [labnetwork] question about Liner for Ni
> Ebeam Evaporation
>
>
>
> We use a Cu crucible (4.4cc in a 7cc pocket) with good results.
>
> Mario
>
>
>
> On 2024-12-11 9:11 a.m., Graham Gibson wrote:
>
> [*CAUTION:* Non-UBC Email]
>
>    It’s interesting to see such a wide variety of experiences. I’m too
> chicken to evaporate right out of the pocket, so we went through a lot of
> liners, too, before settling on something.
>
>
>
>    We have had good luck with Cu liners for Ni e-beam evaporation, but
> with a 2.2 cc pocket, we have to be very careful to keep the beam away from
> the walls and limit the deposition rate to 1 Angstrom/s.
>
>
>
>   Hope you find something that works, liners get expensive!
>
>
>
>
>
> Graham Gibson
>
>
>
> Operations Manager, NanoFabrication Kingston
>
> Queen’s University
>
> 945 Princess Street
>
> Kingston, Ontario, Canada
>
> K7L 0E9
>
> gibsong at queensu.ca
>
> www.nanofabkingston.ca
>
>
>
>
>
>
>
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu>
> <labnetwork-bounces at mtl.mit.edu> *On Behalf Of *Owain Clark
> *Sent:* December 5, 2024 3:48 AM
> *To:* Jeff Salzmann <jks7 at buffalo.edu> <jks7 at buffalo.edu>; Bernhard
> Reineke <bernhard.reineke at uni-paderborn.de>
> <bernhard.reineke at uni-paderborn.de>; shokoofe haghighi
> <shokoofe_haghighi at yahoo.com> <shokoofe_haghighi at yahoo.com>;
> labnetwork at mtl.mit.edu
> *Subject:* Re: [labnetwork] question about Liner for Ni Ebeam Evaporation
>
>
>
> Interestingly we have no trouble with Ni, it is one of our most stable
> materials and the crucible has not been changed in years. I believe it is
> W.
>
>
>
> I suspect reading these comments it is because we have larger 40cc
> crucibles and we only melt a spot in the center with a small beam
> deflection. The crucible walls never see melted Ni.
>
>
>
> BR, Owain
>
>
>
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> *On Behalf Of *Jeff
> Salzmann
> *Sent:* 04 December 2024 17:15
> *To:* Bernhard Reineke <bernhard.reineke at uni-paderborn.de>; shokoofe
> haghighi <shokoofe_haghighi at yahoo.com>; labnetwork at mtl.mit.edu
> *Subject:* Re: [labnetwork] question about Liner for Ni Ebeam Evaporation
>
>
>
> You don't often get email from jks7 at buffalo.edu. Learn why this is
> important <https://aka.ms/LearnAboutSenderIdentification>
>
> *CAUTION:* This e-mail originated outside the University of Southampton.
>
> Haghighi,
>
>
>
> This is my collection of failed crucibles used to evaporate Ni.
>
>
>
> We decided on graphite, because copper was worse. We limit our deposition
> rate to 0.2 Å/sec to help extend the lifespan of the crucibles. They
> still fail after 2-3 depositions.
>
>
>
> Regards,
>
> Jeff
>
>
>
>
>
> Jeff Salzmann
>
> Assistant Professor of Research
>
> Cleanroom Manager, Shared Instrumentation Laboratories
>
> School of Engineering and Applied Sciences
>
> University at Buffalo
>
> 114A Davis Hall
>
> Buffalo, NY 14260
>
> Tel: 716.645.2584
>
>
>
> *From: *labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Bernhard
> Reineke <bernhard.reineke at uni-paderborn.de>
> *Date: *Wednesday, December 4, 2024 at 11:46
> *To: *shokoofe haghighi <shokoofe_haghighi at yahoo.com>,
> labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
> *Subject: *Re: [labnetwork] question about Liner for Ni Ebeam Evaporation
>
> You don't often get email from bernhard.reineke at uni-paderborn.de. Learn
> why this is important <https://aka.ms/LearnAboutSenderIdentification>
>
> Hi Haghighi,
>
> we tried this once, same result. All liners will crack. Lesker has some
> recommendations on Ebeam evaporation of Ni: slow power ramp up and down
> (works well to prevent cracking for ~2-4 Runs, with fabmate). A Cu liner
> should work better but we never tested that.
>
>
> https://www.lesker.com/newweb/deposition_materials/depositionmaterials_evaporationmaterials_1.cfm?pgid=ni1
>
> Best,
>
> Bernhard
> ------------------------------
>
> *Von:* labnetwork <labnetwork-bounces at mtl.mit.edu> im Auftrag von
> shokoofe haghighi <shokoofe_haghighi at yahoo.com>
> *Gesendet:* Mittwoch, 4. Dezember 2024 10:35:19
> *An:* labnetwork at mtl.mit.edu
> *Betreff:* [labnetwork] question about Liner for Ni Ebeam Evaporation
>
>
>
> Hi, hope you are having good days,
>
>
>
> this is Haghighi, working on metallization by a PVD, using thermal and
> Ebeam evaporation.
>
>
>
> I have some issues choosing the right liner for Ni Ebeam evaporating, hope
> you find time to guide me through it.
>
> We have tested graphite, glassy carbon coated graphite, Al2O3, Mo, W and
> Cu liners so far.
>
>     Graphite liner just broke after first run from the border line of Ni
> surface. Glassy carbon coated graphite was more or less the same,
>
>     Al2O3 endured for 4-5 runs before breaking but there were cracks on
> it,
>
>     Mo liner totally melted and some kind of alloy was produced,
>
>     W and Cu endured but their internal walls were some how melted and we
> can't be sure about pureness of evaporated Ni and final produced thin films.
>
>
>
> do you have any other suggestions?
>
>
>
>
>
> high voltage: 6.1 KV
>
> emission current: 3 - 5 A
>
>
>
>
>
> Thanks for your time and attention in advance, I hope you kindly find time
> and consider replying me,
>
>
>
> Dr. Haghighi
>
>
>
>
>
> _______________________________________________
>
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>
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