[labnetwork] Issue Striking Plasma for NiFe Sputtering on Angstrom Nexdep PVD System – Need Guidance

[Matthew Moneck]

Hi Pial,

We run a lot of magnetic materials in our facility, including NiFe.  Most
of our magnetic targets are thicker than 1mm (some up to 3mm depending on
the material), and we typically use 1/8" backing plates as well.
Therefore, your thickness should work well as long as you have enough field
from the magnetron source to penetrate the target.  Since NiFe has very
high permeability, you will need a high strength magnet, such as NdFeB in
your magnetron.

In addition to field strength, the configuration of the magnets can also
make a difference.  For example, our standard cathodes use lower strength
magnets optimized to improve target wear for non-magnetic materials.  When
we run magnetic targets, we need to swap the magnetic assembly for a higher
field design.  I have also worked with cathodes that require replacing a
small magnet in the center of the cathode with a large Fe slug to change
the field profile for magnetic targets in an effort to increase the amount
of field that penetrates the target surface.  Do you know what type of
magnet design or field strength you have?  I am not very familiar with the
Angstrom cathode design, but if I am not mistaken, they do have an
optimized configuration for magnetic targets that is different from their
standard cathode.

One other sanity check is to confirm the current and voltage readouts when
trying to ignite the plasma.  You mentioned that the system turns off the
supply at 15W, so it is likely hitting a limit.  If you do not have enough
magnetic field to trap electrons at the target surface, you should see the
supply hit the voltage limit with no current.  If you see the opposite,
where it fails by hitting a current limit, then you have a short somewhere
(I have seen conductive metal flakes from shields short the target to a
grounded shield for example).

Hope this helps.

Best Regards,

Matt

On Mon, Oct 13, 2025 at 10:33 PM Mohammad Mohtasim Hamid Pial <
mpial001 at fiu.edu> wrote:

> Dear All,
>
> I am attempting to deposit NiFe using a magnetron sputtering setup
> (Angstrom Engineering – Nexdep PVD platform). Below are my target
> specifications and sputtering parameters:
>
> Target: NiFe (2" dia × 1 mm, 4N purity) bonded to a 1/8" Cu backing plate
> Sputtering Method: DC Magnetron Sputtering
> DC Power: 100–150 W
> Base Pressure: ~10⁻⁶ Torr
> Ar Gas Flow Rate: 20–30 sccm
> Working Pressure: 3–5 mTorr
>
> However, I am unable to ignite the plasma. The DC power supply setpoint
> keeps blinking and the power stalls around 15 W before dropping
>
> Could this issue be due to insufficient magnetic field strength (not
> penetrating the thick target/Cu backing), or is the target too thick for
> effective plasma ignition? Do I need a thinner target or additional
> magnetic confinement?
>
> I would greatly appreciate any insights or recommendations from anyone who
> has sputtered NiFe or similar high-permeability alloys on this platform.
>
> Thank you in advance!
> Pial
>
>
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-- 

--
Matthew T. Moneck, Ph.D
Executive Director, Claire & John Bertucci Nanotechnology Laboratory
Electrical & Computer Engineering | Carnegie Mellon University
5000 Forbes Avenue, Pittsburgh, PA 15213-3890
Phone: 412-268-5430
ece.cmu.edu
nanofab.ece.cmu.edu
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