SiO_2/4H-SiC interface doping during post-deposition-annealing of the oxide in N_2O or POCl_3

摘要

In this Letter, we report a quantitative analysis of the n-type doping occurring at SiO_2/4H-SiC interfaces during post-deposition-annealing (PDA) in N_2O or POCl_3 of a 45 nm thick oxide. In particular, a nanoscale characterization using scanning capacitance microscopy on the cross section of metal-oxide-semiconductor capacitors allowed to determine the electrically active nitrogen and phosphorous concentration under the SiO_2 layer after PDA in N_2O and POCl_3, i.e., 5×10~(17)cm~(-3) and 4.5 × 10~(18)cm~(-3), respectively. The technological implications have been discussed considering the possible impact of a PDA-induced "counter doping" of the p-type body region of a n-channel metal-oxide-semiconductor-field-effect-transistor on the device threshold voltage.