4H-SiC n⁺pp⁺ structure passivated with SIPOS-SIO₂ compound layer

A semi-insulating polycrystalline silicon (SIPOS)-SiO₂ compound sheet is used as a passivating layer of 4H-SiC n⁺pp⁺ structure. After the deposition of SIPOS by LPCVD, a unique thermal oxidation step, annealing in oxygen atmosphere at 900°C instead of oxide layer deposition, in normal method is adopted to grow a SiO₂ layer over it. The passivating result demonstrates the reasonability of the alternation. Moreover, the chief technological parameters that influence the passivating effect are also adjusted and the conclusions have been drawn that there should be excess oxygen in SIPOS layer with depositing temperature lower than 1000°C. The annealing temperature should be high up to 900°C. Experimental data show that SIPOS-SiO₂ compound layer can act as an effective passivation sheet of the 4H-SiC n⁺pp⁺ structure to get an ideal breakdown voltage and leakage current.