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

• Published in: IEEE journal of the Electron Devices Society Vol. 11; pp. 438 - 443
• Main Authors: Huang, Hao, Wang, Ying, Chen, Ke-Han, Fei, Xin-Xing
• Format: Journal Article
• Language: English
• Published: New York IEEE 2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 4H-SiC; Aluminum oxide; Annealing; atomic force microscopy; Atomic layer epitaxy; dielectric breakdown field; Dielectrics; Electric fields; Hafnium oxide; High-k dielectric; Hysteresis; Image transmission; Interfacial properties; Leakage current; Logic gates; Metal oxide semiconductors; Microscopy; Silicon carbide; Silicon dioxide; Substrates; transmission electron microscopy; Voltage
• ISSN: 2168-6734
• DOI: 10.1109/JEDS.2023.3296093

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 °C compared with 300 °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/cm2), and the breakdown electric field of the HfO2/SiO2/Al2O3/4H-SiC structure reaches 9.6 MV/cm.