Remote plasma atomic layer deposited Al₂O₃ 4H SiC MOS capacitor with remote H₂ plasma passivation and post metallization annealing

Hydrogen (H₂) plasma treatment at the interface between 4H-SiC substrate and Al₂O₃ dielectric prepared by the atomic layer deposition (ALD) was performed and its effects on capacitance-voltage characteristics as well as the interface state density (D_it) was evaluated with metal oxide semiconductor devices. The atomic force microscopy result indicates that the remote H₂ plasma treatment reduces surface roughness. Compared with the non-passivated devices, lower leakage current, lower hysteresis and higher breakdown voltage are attained with remotely hydrogen plasma-treated devices. Without post metallization annealing (PMA), D_it value more than 10¹⁴ eV^-1 cm^-2 is attained with hydrogen plasma passivated devices, indicating plasma-induced damage on the surface. However, using PMA, D_it of the H₂ plasma treated device is significantly reduced to as low as 1.00 × 10¹² eV^-1 cm^-2 at E_c - E_t = 0.4 eV and is about five times lower than that of sample without H₂ plasma passivation (D_it = 4.84 × 10¹² eV^-1 cm^-2).