Time resolved diagnostics of a HiPIMS discharge with positive cathode reversal

Jeckell, Zachary Jon

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https://hdl.handle.net/2142/129309 Copy

Description

Title

Time resolved diagnostics of a HiPIMS discharge with positive cathode reversal

Author(s)

Jeckell, Zachary Jon

Issue Date

2025-05-02

Director of Research (if dissertation) or Advisor (if thesis)

Ruzic, David N

Doctoral Committee Chair(s)

Ruzic, David N

Committee Member(s)

• Jurczyk, Brian
• Andruczyk, Daniel
• Rovey, Joshua

Department of Study

Nuclear, Plasma, & Rad Engr

Discipline

Nuclear, Plasma, Radiolgc Engr

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• HiPIMS
• Plasma Diagnostics
• Time resolved
• Sputtering
• Magnetron

Abstract

High Power Impulse Magnetron Sputtering (HiPIMS) with positive cathode reversal, or the kick pulse, is an emerging technology in the coating sphere that shows a substantial amount of promise due to the high degree of target material ionization and energetic control available. This work aims to study these discharges utilizing a variety of time resolved diagnostics in an effort to better understand their temporal evolution. Throughout this work multiple different sputtering targets were investigated, mainly zirconium, silver and titanium. This work is an extension of years worth of research at the Center for Plasma-Material Interactions (CPMI) in the topic of physical vapor deposition. This work begins with presenting some preliminary findings with our time resolved Langmuir probe set up which shows that the plasma potential increases after the kick pulse turns on after about 1-2 μs. Simultaneously we were able to use the IMPEDANS Semion probe to study the time evolution of the ion energy distribution function (IEDF), where we show that the ion energy increases over the same time scale as the plasma potential. A high energy tail was seen at the start of the kick pulse, which we hypothesized were metal ions that had their plasma potential increased enroute to the substrate which we called the early kick. The evolution of the discharge was also studied using an intensified charge-coupled device (ICCD) to study the formation of a plasma instability known as hot spots and to see if they appear when a prior model predicted. Through this study we found good agreement with the model and also found that for silver at high enough currents the hot spots are suppressed. A great deal of the work presented in this manuscript is using the HIDEN plasma sampling mass spectrometer (PSM) to study the time and energy resolved mass spectrums of the ions present in the HiPIMS discharge. Through this we confirmed that the high energy tail present at the start of the kick pulse was from metal target ions. Using this PSM we were able to show that the measured IEDF for nitrogen is very similar to the measured IEDF for titanium when performing titanium nitride experiments which suggests that the nitrogen ions are primarily sputtered from the target. Additionally, using the PSM we were able to investigate the IEDF of the ions perpendicular to the target as well. It was found that they also see an increase in their energy showing that the plasma potential is increasing throughout the volume of the chamber. Interestingly, it was found that the ratio of metal ions to argon ions is drastically higher perpendicular to the target than it was on axis. Through this research we also observed the presence of ions with thruster like ion energy distributions which were highly dependent on discharge conditions such as pressure and throw distance. Time resolved Langmuir probe measurements and perpendicular ICCD measurements were also taken to see if plasma expansion was occurring at the start of the kick pulse which we did find some evidence of. This may be part of the explanation for why the metal ion to argon ion ratio is drastically different between the two configurations. Using what we learned from the titanium nitride diagnostics a brief experimental campaign was performed and titanium nitride was deposited at room temperature with ideal stoichiometry with a measured hardness of 26.49 GPa.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129309

Copyright and License Information

Copyright 2025 Zachary Jeckell

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