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

[Alex Dixon]

For magnetic materials the standard recommendation is 0.125 thick target with a spacer ring, and mount directly to the gun without a backing plate or Cu mesh, however I have been able to sputter 1/4" thick magnetic targets as long as they are directly mounted.

Also, did you remove the center magnet stack from the gun and replace with a Fe slug prior to loading your target?

-Alex

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Alex Dixon, Ph.D. (He/Him)
Lab Manager
Nanofabrication and Thin Film Deposition
Shared Instrument Facility
Colorado School of Mines

________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Jing Guo <jg78 at rice.edu>
Sent: Monday, October 13, 2025 9:18 PM
To: Mohammad Mohtasim Hamid Pial <mpial001 at fiu.edu>
Cc: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
Subject: [EXTERNAL] Re: [labnetwork] Issue Striking Plasma for NiFe Sputtering on Angstrom Nexdep PVD System – Need Guidance

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Hi Pial,

Usually for magnetic target, it cannot be a thick one (typically 1-3mm). Otherwise the magnetic field is shunting which will result in plasma strike failure. When I install the magnetic target on AJA tool, there is no bonding Cu backing plate, the Fe or Ni target will be installed directly onto the sputter gun. I think your target thickness is fine, but the backing plate is a problem. You should check with Angstrom sputter engineers about their system setup.
 Another concern is the striking pressure, usually I use a high pressure to strike (20-30mTorr), then reduce the pressure to 3-5mTorr for deposition.

I feel the bonded target thickness is the biggest problem.



Best,
Jing

---------------------------------------
Jing Guo Ph.D.
Cleanroom Manager/Research Scientist
SEA Cleanroom (SST 017)
Rice University
Houston, TX
jeanne.guo at rice.edu
713-348-8227

On Oct 13, 2025, at 3:32 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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