SIC DOPANT INCORPORATION CONTROL USING SITE-COMPETITION CVD

The use of site-competition epitaxy, which is based on intentional var iation of the Si/C ratio during epitaxy, has now been reproduced in nu merous national and international laboratories. Presented in this pape r is a summary of the site-competition technique as a comparison of co ntrolled doping on C-face 6H-SiC(<000(1)over bar>) versus Si-face BH-S iC(0001) substrates for phosphorous (P), aluminum (Al), boron (B), and nitrogen (N). Also reported herein is the detection of hydrogen in bo ron-doped CVD SiC epilayers and hydrogen-passivation of the boron-acce ptors, Results from low temperature photoluminescence (LTPL) spectrosc opy indicate that the hydrogen content increased as the C-V measured n et hole concentration increased. Secondary ion mass spectrometry (SIMS ) analysis revealed that the boron and the hydrogen incorporation both increased as the Si/C ratio was sequentially decreased within the CVD reactor during epilayer growth. Boron-doped epilayers that were annea led at 1700 degrees C in argon no longer exhibited hydrogen-related LT PL lines. and subsequent SIMS analysis confirmed the outdiffusion of h ydrogen from the boron-doped SiC epilayers. The C-V measured net hole concentration for the B-doped epitaxial layers increased more than thr ee-fold as a result of the 1700 degrees C anneal, which is consistent with hydrogen passivation of the boron-acceptors. For N-doped epitaxy, N incorporation into C-sites is favored on the Si-face whereas N inco rporation into the Si-site is apparently the preferred lattice site on the C-face. Both P and N exhibit preferred incorporation on the C-fac e while Al and B incorporation is more efficient on the Si-face.