Dependence of DAP Emission Properties on Impurity Concentrations in N-/B-co-doped 6H-SiC

The dependence of donor-acceptor pair (DAP) emission properties on impurity concentrations of N and B in 6H-SiC epilayers was investigated. Doped samples were grown by closed sublimation technique, and impurity concentrations were confirmed by secondary ion mass spectrometry (SIMS). Photo luminescence (PL) measurement results indicate that p-type 6H-SiC with N-A > N-D had extremely low DAP emission efficiency, whereas n-type 6H-SiC with N-A < N-D showed intense DAP emission. Moreover, n-type 6H-SiC with high N and B concentrations exceeding 10(18)cm(-3) is preferable for high DAP emission efficiency.