Challenging atomistic processes in SiC

This proposal addresses fundamental issues regarding atomistic phenomena occurring during modification and processing of silicon carbide (SiC). SiC is a novel wide bandgap semiconductor with an outstanding potential beyond the silicon era. However, to rea lize this potential, a number of critical scientific challenges need to be resolved, and two of the most commonly recognized ones are tackled here, i.e., 'gate dielectrics' and 'selective area doping'. Al2O3 and ZrO2 will be grown on epitaxial 4H- and 6H- SiC layers by ALCVD, and the electrical and structural properties of the oxide/SiC interface will be studied in detail. An ultimate goal is to gain understanding about the identity of near-interfacial electron traps and how their density and energy distri bution can be controlled. Focused beams of electrons/ions will be employed to reveal the intriguing phenomenon of long distance defect migration (>300 microns) outside the directly irradiated area in SiC. The process is athermal and may be one of the very first confirmations of the Bourgoin-Corbett mechanism for charge-state driven migration. Laterally resolved electrical and optical characterization techniques are to be used, and the experimental concept is quite unique/original since it also facilitates identification of defects involving carbon interstitials. The crucial but scarcely studied EH6/7 deep-level defect in 4H-SiC will be investigated with respect to identity and mechanisms for formation and annealing. In particular, epitaxial layers grown u nder different conditions, like variation of the C/Si ratio and using different n-type dopants, will be subjected to electron/ion irradiation and electrical characterization. The project is planned for 2 PhD students and 1 visiting scientist, and excellen t facilities exist at the MiNaLab in Oslo for sample growth, modification and analysis. Further, the project comprises extensive collaboration with leading international and national research partners.