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

Abstract

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 (Dit) 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), Dit value more than 1014eV−1cm−2 is attained with hydrogen plasma passivated devices, indicating plasma-induced damage on the surface. However, using PMA, Dit of the H2 plasma treated device is significantly reduced to as low as 1.00×1012eV−1cm−2 at Ec−Et=0.4eV and is about five times lower than that of sample without H2 plasma passivation (Dit=4.84×1012eV−1cm−2).