Experimental and computational investigation of tin interaction with hydrogen gas

Extreme ultraviolet light sources, which are used in industry to produce top-of-the-line computer chips, are susceptible to short lifetimes due to tin build-up inside the machines. Tin, which generates the light, coats sensitive components inside the source vessel after being struck with a high-power laser. Hydrogen is used as a buffer gas to prevent tin from reaching the walls, but the mechanisms of the tin and hydrogen interactions are poorly understood. In this thesis, these interactions are studied computationally and experimentally. A computer model was built using density-functional theory to generate Sn − H2 and Sn2+ − H2 interaction potentials which were implemented in scattering code RustBCA. Results from the computer model were compared against other common models, which generally showed that tin travels farther in hydrogen at energies below 10 keV and less far at energies above 10 keV than previously thought. An experiment was built with a Faraday cup to measure tin ion current generated by an ion gun at several of ion energies in the HARP vacuum system. Energies from 500 to 1250 eV were measured and the cross section was calculated from the data. The experimental measurements generally showed a cross section larger than the model’s cross section by a factor of 5, which in turn was larger than other measurements in literature. Hydrogen plasma generated with a helicon was also compared against hydrogen gas, and the plasma stopped the tin ion beam slightly more efficiently. Systemic biases and measurement uncertainties in the experimental results suggest that more work is needed in this area.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Nuclear, Plasma, Radiolgc Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Stahl, Jack Thomas

Contributors dc:contributor

• Ruzic, David N
• Sankaran, Mohan

• tin
• hydrogen
• plasma
• ion
• scattering
• RustBCA
• ion gun

Statement dc:rights

• Copyright 2022 Jack Stahl

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/116287

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F116287