Remote plasma atomic layer deposited Al2O3 4H SiC MOS capacitor with remote H-2 plasma passivation and post metallization annealing

Abstract

Hydrogen (H-2) 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 H-2 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 10(14) 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 H-2 plasma treated device is significantly reduced to as low as 1.00 x 10(12) eV(-1) cm(-2) at E-c - E-t = 0.4 eV and is about five times lower than that of sample without H-2 plasma passivation (D-it = 4.84 x 10(12) eV(-1) cm(-2)).