Estimation of Ionization Coefficients of Gallium Oxide for the Purpose of TCAD Simulation
thesisposted on 27.11.2018 by Giftsondass Irudayadass
In order to distinguish essays and pre-prints from academic theses, we have a separate category. These are often much longer text based documents than a paper.
Gallium oxide is not a novel material, but has been overlooked in favor of semiconductors like gallium nitride and silicon carbide. It is a typical ultra-wide bandgap material and has attractive material properties represented by its extremely large bandgap of 4.85 eV. Recent revolution in its bulk single crystal growth methods has inspired scientist to research more on this material. Though the research on the material has picked up, there is still a lot of ground to cover to catch up to standard commercialized semiconductors. TCAD's have inspired their own line of research based on the understanding of device physics, and most TCADs are tailored to standard semiconductors. In this thesis we address one such device physics required to determine the breakdown voltage of gallium oxide devices, the physics of impact ionization. We use known physical properties of gallium oxide in standard models to obtain an estimate of the ionization coefficients. We also determine certain properties, essential for the estimation of the coefficients, based on approximation models. The estimates are compared with GaN and SiC and is found to be higher in gallium oxide as expected.