Characterization of an Inductively-Coupled Plasma Immersion Ion Implantation System
| dc.contributor.advisor | Couedel, Lenaic | |
| dc.contributor.advisor | Bradley, Michael P | |
| dc.contributor.committeeMember | Koustov, Sasha | |
| dc.contributor.committeeMember | Xiao, Chijin | |
| dc.contributor.committeeMember | Zhang, Lifeng | |
| dc.contributor.committeeMember | Moewes, Alexander | |
| dc.contributor.committeeMember | Stafford, Luc | |
| dc.creator | Moreno, Joel Thomas | |
| dc.creator.orcid | 0000-0001-7038-3826 | |
| dc.date.accessioned | 2023-09-25T22:23:11Z | |
| dc.date.available | 2023-09-25T22:23:11Z | |
| dc.date.copyright | 2023 | |
| dc.date.created | 2023-08 | |
| dc.date.issued | 2023-09-25 | |
| dc.date.submitted | August 2023 | |
| dc.date.updated | 2023-09-25T22:23:11Z | |
| dc.description.abstract | The field of materials processing has been one of the most important driving forces behind technological advancements in the last several decades. Surface modification by ion implantation, deposition or etching has benefited products ranging from integrated circuit chips, solar panels, diodes, biomaterials, television screens, and heavy-duty industrial tools. The initial approach, termed conventional beamline ion implantation (CBII), involved generating ions in a separate chamber and extracting, directing and accelerating them toward the object targeted for treatment. This line-of-sight process required a complex system of object manipulation, making uniform surface treatment a lengthy process for any object that is not small and simple in shape. Plasma immersion ion implantation, or PIII, was developed in the 1980's as an alternative to CBII. PIII operates by immersing the target directly in the source of ions, i.e. the plasma. Then, negative-polarity high voltage (HV) pulses are applied to the target, creating a strong electric field between the bulk plasma and the target surface, or a sheath. This sheath develops perpendicularly to the surface, extracting ions from the source and directing them into the surface. This approach allows independent control of ion fluence, which depends on the density of the plasma generated, and incident ion energy, which is determined by the magnitude of the applied HV pulse. The dosage tends to be highly uniform for any object shape and can be completed much more quickly than with CBII. Furthermore, this process avoids the more complex elements of ion translation and object manipulation of CBII. PIII, therefore, has gained popularity in materials science, particularly for large or irregularly shaped objects. It should be clear, based on the description of this process, that HV sheaths are a fundamental aspect of PIII. Most industrial applications of PIII, though, rely on a simplified model of HV sheath dynamics and empirical recipes of operational parameters (e.g. power and pressure). This can lead to material waste and an unpredictable and inconsistent ion implantation depth and dose. In order to improve process control and efficiency, developing a comprehensive HV sheath model based on experimental data is critical. However, the relationship between the sheath and the bulk reservoir of ions is highly non-linear, making the derivation of a self-consistent solution to the governing equations complex. Direct measurements of plasma parameters during processing are also difficult to obtain. This is due to the high time-resolution required to measure evolving plasma dynamics during the HV pulses, as well as the high spatial-resolution necessary to investigate the often sub-centimetre sheath lengths. As a result, many consequential characteristics of ion implantation are neglected and second-order physical phenomena that may have a large impact on the overall process efficiency go undetected. Many conventional plasma diagnostics and their data acquisition methods common in industrial PIII chambers cannot provide this resolution, and cannot measure ion properties with great detail, if at all. Furthermore, alternatives are often costly and have not been thoroughly researched. The goal of the experimental work performed and presented in this thesis, therefore, is to characterize plasma dynamics during HV ion implantation with greater temporal and spatial detail. The former is achieved by applying a time-resolved data acquisition technique to Langmuir probe measurements. This revealed a perturbation in plasma properties, i.e. density, temperature and potential, that occurs in the bulk plasma far beyond the length of the HV sheath. This phenomena was unexpected because standard models assume that the sheath and the bulk plasma are de-coupled. However, the most extensive experimental work was constructing a laser-induced fluorescence (LIF) apparatus and collecting spectroscopic measurements of ion properties. Due to a number of factors such as complexity and cost, this is one of very few LIF diagnostics implemented for PIII characterization. In addition to the millimetre-length spatial resolution it provides, LIF measures ion temperature and directed velocity with unparalleled precision. Direct measurements of these ion characteristics are critical to developing a more complete and accurate predictive model of PIII processing. For example, by including direct measurements of ion impact energy gained across the sheath in the model, more precise deposition profiles may be reached more efficiently. As this is a newly built apparatus, the data acquisition, processing and error analysis routine is thoroughly documented to ensure these initial results are accurate. These results are then found to be overall consistent with theory and previously published research. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/10388/15061 | |
| dc.language.iso | en | |
| dc.subject | Experimental Plasma Physics, Diagnostics | |
| dc.title | Characterization of an Inductively-Coupled Plasma Immersion Ion Implantation System | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Physics and Engineering Physics | |
| thesis.degree.discipline | Physics | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy (Ph.D.) |