Dissertation Defence: Optical examination of silicon thin-films grown by ultra-high-vacuum evaporation

Sin Hang Cheung, supervised by Dr. Stephen K. O’Leary, will defend their dissertation titled “Optical examination of silicon thin-films grown by ultra-high-vacuum evaporation” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering.

An abstract for Sin Hang Cheung’s dissertation is included below.

Examinations are open to all members of the campus community as well as the general public. This exam will be held in hybrid format. Registration is not required to attend in person; however, please email stephen.oleary@ubc.ca for the Zoom link.

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Abstract

This thesis draws upon experimental data sets harvested from experiments performed on a collection of ultra-high-vacuum evaporation-prepared thin silicon film samples, these experiments being performed by researchers from the National Research Council of Canada. A molecular beam epitaxy deposition set-up was commissioned for the thin-film preparations, the hydrogen content found within these thin-films being considerably less than those prepared through the use of conventional thin-film silicon preparation techniques. For this reason, we suspect the ultra-high-vacuum evaporation prepared thin silicon films will be less susceptible to the instability that bedevils more conventional forms of thin-film silicon. These thin-film silicon samples are grown for a number of different growth temperatures on a number of substrate selections. Characterizations are performed, including those based on grazing incidence X-ray diffraction and Raman spectroscopy, these probing each thin silicon film’s microstructure. Noting that differences in processing thin-film silicon’s Raman spectral data can lead to quantitative differences in the Raman-related metrics that arise as a corollary, a series of critical steps for processing Raman spectral data associated with thin-film silicon are suggested. In order to provide some sense as to how these steps influence the form of the Raman spectrum, the post-processing steps are performed on representative thin-film silicon Raman spectral data sets. The processed data is then further analyzed in parallel with the grazing incidence X-ray diffraction data. From the diffraction patterns, through applying Scherrer’s equation, the crystallite dimensions’ dependence on the growth temperature is resolved for each considered thin silicon film. From the Raman spectral decompositions, the location, breadth, and character of each identified peak is noted, the evolution of these decompositions in response to growth temperature variations being examined for the different substrate selections. Finally, following some general discussion on the results, where these thin-films of silicon can be placed into the thin-film silicon continuum is examined.