Irradiation experiments have been performed 60° off the surface normal for 6H-SiC single crystals at various temperatures (185-870 K) using 550.keV Cions over a fluence range from IxlO18 to 5x10" ions/m2. Atomic disorder on the Si sublattice, as determined by in-situ RBS/channeling analysis, ranged from dilute defects to complete amorphization. The critical amorphization dose of -0.23 dpa (on the Si sublattice) at 185 K has been determined. Asymmetric shapes in angular yield profiles across the crystallographic axis <0001> emerged above 1.5x10" CVm2 (-0.05 dpa in the near-surface region), which might be associated with the lattice disturbance in the crystal structure. A gradual decrease in half-angular width was observed with the increase of ion fluence in the experiment. The minimum yield exhibits a rather linear relationship with ion dose at the surface. Post-irradiation annealing at the irradiation temperature did not result in measurable recovery for fluences ranging from 4x10" to 2x10" CVm2 at 300, 470 and 670 K. Results also show that low fluence (<8xl018 CVm2) irradiation at 185 K followed by thermal annealing results in similar defect concentrations to irradiation at that same temperature to the same ion fluence. Thus, at low fluences, the accumulated defects are in thermal equilibrium with the structure.
|Title of host publication||Materials Research Society Symposium - Proceedings|
|Number of pages||6|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials