TY - JOUR TI - Structure and chemistry of defect passivation at the interface between silicon dioxide and silicon carbide DO - https://doi.org/doi:10.7282/T3CV4KB5 PY - 2014 AB - Silicon carbide (SiC) is a wide bandgap semiconductor which has material properties well-suited for high-power, high-temperature electronics applications. The performance of SiC transistors is limited by electrical defects formed at the SiO2/SiC interface under high temperature oxidation. A central goal of this work is to improve our atomic level understanding of electrical defects in SiC devices, and to further develop methods to minimize defects. Introduction of interfacial nitrogen (N) or phosphorus (P) reduces the interface (charge) trap density, increases the SiC charge mobility (in the semiconductor channel), and thus device performance. This dissertation is focused on the chemistry of the SiO2/SiC interface, the critical interface in future SiC-based devices. We address issues of composition, structure, chemical bonding, and reaction behavior of N and P that we have used to improve device performance. We report photoemission and ion scattering studies to determine the concentrations of N and P passivating agents at the SiO2/SiC interface, and develop a more complete understanding of the mechanism and kinetics for the passivation processes on different crystallographic surfaces. The study shows that N (and P) passivated SiO2/SiC structures have a thin oxy-nitride (oxy-phosphide) interface dielectric layer that cannot be removed by a buffered HF etchant. The same dielectric structures are completely etched when formed on Si. Atomic scale modeling, combined with our experimental observations, results in the suggestion of likely bonding structures of N and P at the SiO2/SiC interface. The depth profile of N and P at SiO2/SiC interface has also been established and provides further insights into the nature of N and P as surface passivating additives. KW - Chemistry and Chemical Biology KW - Silicon carbide--Electric properties LA - eng ER -