Defects in 4H-SiC Layers Grown by Chloride-Based Epitaxy
Chloride-based 4H-SiC epitaxial layers were investigated by DLTS, MCTS and PL. The DLTS spectra of the as grown samples showed dominance of the Z1/2 and the EH6/7 peaks. For growth rates exceeding 100 µm/h, an additional peak occurred in the DLTS spectra which can be assigned to the UT1 defect. The shallow and the deep boron complexes as well as the HS1 defect are observed in MCTS measurements. The PL spectra are completely dominated by the near band gap (NBG) emission. No luminescence from donor-acceptor pair occurred. The PL line related to the D1 centre was weakly observed. In the NBG region nitrogen bound exciton (N-BE) and free exciton (FE) related lines could be seen. The addition of chlorine in the growth process gives the advantage of high growth rates without the introduction of additional defects.
Amador Pérez-Tomás, Philippe Godignon, Miquel Vellvehí and Pierre Brosselard
F. C. Beyer et al., "Defects in 4H-SiC Layers Grown by Chloride-Based Epitaxy", Materials Science Forum, Vols. 615-617, pp. 373-376, 2009