Date of Award
Doctor of Philosophy
Materials Science and Engineering
William J. Weber
Energetic ions deposit their energy into a target material through elastic and inelastic processes: termed nuclear and electronic energy loss. In SiC [silicon carbide], these two processes are coupled and often competing, where nuclear energy loss generates defects and disorder, and electronic energy loss anneals the material. This work examines the relationship between these energy deposition processes and their impact on single crystal, 3C- and 4H-SiC microstructure via intermediate energy ion irradiations. With increasing incident ion atomic mass, decoupling between the two processes takes place, and inelastic energy deposition becomes less effective at inducing in-cascade annealing. Further, there are thresholds in electronic energy loss above which, disorder induced by damage energy is totally suppressed. These thresholds increase sub-linearly with incident ion atomic number. The feasibility of inelastic energy deposition inducing dopant activation is also studied. While 21 MeV Ni irradiation failed to activate implanted As ions, the irradiation did reduce implantation damage and altered the disorder and defect distribution in SiC. Overall, electronic energy loss from intermediate to higher energy ions can significantly alter physical disordering processes and electrical properties in SiC.
Nuckols, Lauren, "Ion Irradiation Effects on Damage Annealing and Dopant Activation in Single Crystal SiC. " PhD diss., University of Tennessee, 2021.