Thesis Format
Integrated Article
Degree
Master of Science
Program
Physics
Supervisor
Goncharova, Lyudmila V.
2nd Supervisor
Simpson, Peter J.
Affiliation
University of British Columbia
Co-Supervisor
Abstract
SiGeSn compounds are tunable semiconductors offering flexibility in lattice parameters and band structure, making them promising for integrating electronic and photonic devices. Applications include lasing, waveguides, high electron mobility transistors, and fully depleted metal-oxide-semiconductor field-effect transistors. This study examined the optical and material properties of 20 - 60 nm SiGeSn layers fabricated by ion implantation on Si (001) substrates, using techniques such as Spectroscopic Ellipsometry (SE), channeling Rutherford Backscattering Spectroscopy (c-RBS), Positron Annihilation Spectroscopy (PAS), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Analysis (EDX). RBS verified Ge and Sn implantation depth profiles and doses, and showed Ge accumulation at the SiO2/Si interface, and peak Ge concentrations of 25–75 at.%. SE modeling, supported by RBS data, showed a ~50 nm thick implanted layer with enhanced near-IR absorption. Annealing increased Ge and Sn substitutionality with the highest values at 800°C while reducing defects. The study demonstrated that annealing improved the structural and optical properties of SiGeSn layers, particularly enhancing near-IR and short-wave-IR absorption compared to Si. Ge and Sn incorporation into the silicon lattice increased with annealing temperatures above 600°C, reducing defect densities and promoting substitutionality of Ge and Sn. Notably however, Sn clustering occurred at higher temperatures (>800°C). Optimized samples exhibited strong absorption beyond 1100 nm, attributed to high Ge and Sn incorporation, making them suitable for those optoelectronic applications in which absorption is desirable, such as detectors and photovoltaics.
Summary for Lay Audience
This research investigates improving communication technology by integrating electronic and optical components on a single chip. This integration could simplify the design of devices such as smartphones and data centers. The study focuses on silicon-germanium-tin (SiGeSn) semiconductors, a material system that offers precise control over structural and electronic properties, making it suitable for applications such as lasers, optical waveguides, and high-speed transistors.
The research examined thin films of SiGeSn, between 20 to 60 nanometers thick, grown on silicon substrates. Advanced techniques, such as Rutherford Backscattering Spectroscopy (RBS) for analyzing germanium (Ge) and tin (Sn) distribution and Spectroscopic Ellipsometry (SE) for optical behavior, were used. Additional methods, including Positron Annihilation Spectroscopy (PAS) and Scanning Electron Microscopy (SEM), characterized the structure, morphology, and defects in the layers.
Results demonstrated successful integration of Ge and Sn into the silicon lattice, with their distribution influenced by heat treatments. Ge concentrations near the SiGeSn-oxide interface reached up to 75% in some samples, enhancing the material’s ability to absorb light in the near- and short-wave infrared range. Models based on experimental data confirmed that SiGeSn layers absorb near-infrared light more effectively than silicon, which is valuable for devices like optical sensors and lasers. The research highlights SiGeSn’s compatibility with existing silicon manufacturing processes, providing a cost-effective path to producing optoelectronic devices. These findings emphasize the potential of SiGeSn alloys for efficient near-infrared light absorption, advancing integrated photonic and electronic technologies.
Recommended Citation
Henry, Alexander W., "Tailoring the Optical and Structural Properties of SiGeSn by Ion Implantation" (2025). Electronic Thesis and Dissertation Repository. 10716.
https://ir.lib.uwo.ca/etd/10716
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
