Effect of high-temperature processing on the creation of boron-related deep levels in 4H-SiC

Abstract

High-temperature processing was applied to SiC boron-doped epitaxial layers, epitaxial layers grown on boron-rich substrates, and boron-implanted samples in order to establish conditions favorable for the formation of boron-related centers (D-centers) that introduce a deep level in SiC bandgap. Photoluminescence (PL) was used to detect and compare the formation of the D-center after different processing steps. It was confirmed that the presence of lattice defects was required for achieving significant boron diffusion and D-center formation. In addition, epitaxial growth on the top of a boron-implanted sample yielded efficient boron in-diffusion in the growing layer, which resulted in a material compensated with D-centers. The temperature dependence of the D-center formation efficiency was investigated.