Damage behaviour and annealing of germanium implanted 6H-SiC

The present paper reports a study of the defect reduction
and recrystallization during annealing of Ge+-implanted 6H-SiC. Implants
have been performed at 200 keV with doses of 1x1014 and 1x1015 cm-2. Furnace
annealing has been carried out at temperatures of 500°, 900° and
1500 °C. Several analytical techniques including Rutherford backscattering
spectrometry in conjunction with channeling (RBS/C), cross-sectional transmission
electron microscopy (XTEM), positron annihilation spectroscopy (PAS), Raman
scattering (RS), and electron paramagnetic resonance (EPR) measurements
have been employed for sample characterization. It has been shown that
damage removal is more complicated than in ion-implanted Si. Using PAS
deeply diffusion vacancy-like defects were found far below the region defined
by TRIM as containing the maximum amount of nuclear energy deposition.
The amorphized SiC is characterized by carbon dangling bonds as revealed
by EPR. The recrystallization of amorphized SiC layers has been found to
be unsatisfactory for temperatures up to 1500 °C. The use of ion-beam-induced
epitaxial crystallization (IBIEC) has been more successful as lattice regrowth,
altough still imperfect, has been observed to occur at a temperature
as low as 500 °C.