[labnetwork] Crucible damage in e-beam evaporator

[James Mitchell]

I would check your beam steering. You made need to adjust where it is
dropping.
Also check the wiring to beam steering magnets on the e-gun. If a wire is
broken it could cause misdirection.
Next, you may need to clean or replace the hearth assembly. You may be
losing conductivity under the crucible due to buildup.

Jim

On Mon, Dec 13, 2021 at 7:51 AM Savitha P <savithap at iisc.ac.in> wrote:

>
>
> Hi,
>
> We use a Leybold univex 400 with EV M-8 ferrotec e-gun assembly for out
> metal coatings. We have been using an optimized recipe for Al deposition in
> Cu crucibles for long.
>
> Power % : Raise 1: 10% (V= 10 KV and I ~ 110 mA), 5 mins, hold 2 mins
>                 Raise 2: 22% (V= 10 KV and I ~ 220 mA), 5 mins, hold 2 mins
>                 During the deposition Power % goes up to 24% and the current
> goes up to 240 mA ( V = 10 KV constant)
>
> Some spit is seen during raise 2.
>
> But recently we got serious concern of Cu crucible melting, mostly towards
> the gun side. We set the beam as spot pattern (for Ti, beam profile is
> infinity pattern), but it looks elongated. Beam is centred well.  We set
> the deposition rate to 0.3 nm/sec. Hearth cooling is done at 20 deg C, with
> water flow rate at 6 litre per minute. Al source fill in crucible is around
> 70-80%. Beam ramp down is 5 minutes. Chamber venting is set after 25
> minutes.
>
> We used an infinity beam pattern to deposit a thick Al metal coating
> sometime back. We changed all our settings back to spot pattern again. This
> issue started after that. Seems, somehow the beam did not come back to
> previous focus.
>
> We need to know, has anyone came across something like this, and how to
> overcome this. Any information would be helpful.
>
> Thanks.
>
> Savitha
>
> Dr. Savitha P
> Chief Operating Officer
> National Nanofabrication Centre
> Centre for Nanoscience and Engineering
> Indian Institute of Science
> Bangalore - 560012
> India.
> Ph. +91 80 2293 3319
> www.cense.iisc.ac.in
>
>
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-- 
*James Mitchell*
*Specialty Trades Technician*
*Dept. of Electrical and Computer Engineering*
*NCSU Nanofabrication Facility*
*MRC RM243A **Box 7911*
*2410 Campus Shore Dr., Raleigh, NC 27606*
*jtmitch5 at ncsu.edu* <jtmitch5 at ncsu.edu>
*Desk: 919-515-5394*
*Cell: 919-717-7325*
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