Leakage Current Behavior in HfO2/SiO2/Al2O3 Stacked Dielectric on 4H-SiC Substrate

In this study, we investigate the deposition of high-k dielectric materials, namely Al2O3 and HfO2, using atomic layer deposition for 4H-SiC metal-oxide-semiconductor applications. C-V measurements reveal that the HfO2/SiO2/Al2O3/4H-SiC structure exhibits lower interface state density (Dit) and a reduced number of fixed interface trap charges (Neff) than the HfO2/Al2O3/SiO2/4H-SiC structure. Furthermore, we observe significant degradation of the interface properties when annealing at 400 degrees C compared with 300 degrees C, as evidenced by atomic force microscopy images. Transmission electron microscopy analysis shows that the SiO2/SiC surface is inhomogeneous and contains carbon clusters, while the Al2O3/SiC interface displays a more uniform structure. The I-V curves demonstrate a reduced leakage current for the high-k dielectric stacked structure to (10-11 A/cm(2)), and the breakdown electric field of the HfO2/SiO2/Al2O3/4H-SiC structure reaches 9.6 MV/cm.

Automated summary

This study investigates the deposition of high-k dielectric materials, Al2O3 and HfO2, on 4H-SiC for metal-oxide-semiconductor applications using atomic layer deposition. The HfO2/SiO2/Al2O3/4H-SiC structure shows lower interface state density (Dit) and reduced number of fixed interface trap charges (Neff) compared to the HfO2/Al2O3/SiO2/4H-SiC structure. Interface properties degrade significantly when annealed at 400 degrees C. Transmission electron microscopy analysis reveals an inhomogeneous SiO2/SiC surface with carbon clusters and a more uniform Al2O3/SiC interface. The high-k dielectric stacked structure exhibits reduced leakage current (10-11 A/cm(2)) and a breakdown electric field of 9.6 MV/cm.