TEOS-based low-pressure chemical vapor deposition for gate oxides in 4H-SiC MOSFETs using nitric oxide post-deposition annealing

The use of SiO2/4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) can be problematic due to high interface state density (D-it) and low field-effect mobility (mu(fe)). Here, we present a tetra-ethyl-ortho-silicate (TEOS)-based low-pressure chemical vapor deposition (LPCVD) method for fabricating the gate oxide of 4H-SiC MOSFETs using nitric oxide post-deposition annealing. SiO2/4H-SiC MOS capacitors and MOSFETs were fabricated using conventional wet and TEOS oxides. The measured effective oxide charge density (Q(eff)) and D-it of the TEOS-based LPCVD SiO2/4H-SiC MOS capacitor with nitridation were 4.27 x 10(11) cm(-2) and 2.99 x 10(11) cm(-2)eV(-1), respectively. We propose that the oxide breakdown field and barrier height were dependent on the effective Q(eff). The measured mu(fe) values of the SiO2/4H-SiC MOSFETs with wet and TEOS oxides after nitridation were, respectively, 11.0 and 17.8 cm(2)/V due to the stable nitrided interface between SiO2 and 4H-SiC. The proposed gate stack is suitable for 4H-SiC power MOSFETs.