Characterization of Defects Generated During Boron Diffusion in SiC

The defects associated with the implantation and diffusion of boron in silicon carbide have been studied using secondary ion mass spectrometry (SIMS) and photoluminescence (PL) imaging and spectroscopy. An n-type epitaxial SiC (1000) substrate was implanted with 2×1014 atoms/cm2 B and annealed to 1700°C. PL data was acquired before and after annealing, and following removal of various thicknesses of the sample by mechanical polishing. Thermal annealing generated a B diffusion profile measured by SIMS to extend to about 3 microns depth. After removing the diffused B layer, a PL spectral feature at 415nm disappeared, which is consistent with its previous identification as arising from donor-acceptor pairs (DAP). The D1 spectral features survived polishing, supporting previous suggestions that these features are intrinsic defects due to the di-interstitial (Ic-Ic or Isi-Isi) or di-vacancy (Vc-Vc or Vsi-Vsi) defects.