The changes of the defect states below the conduction band in atomic-layered HfO2 film grown on SiC substrate were examined as a function of the post-nitridation annealing temperature in an NH3 ambient. As the post-nitridation annealing temperature increased up to 600 °C, the incorporated nitrogen into the HfO2/SiC interface was gradually increased. The band gap and valence band offset were mostly increased as a function of the post-nitridation annealing temperature and the band alignment of HfO2 films changed. O K-edge absorption features revealed two distinct band edge states below the conduction band edge in HfO2 films, and these defect states were dramatically reduced with increasing of the post-nitridation annealing temperature. The reduction of defect states in HfO2/SiC improved the electrical properties such as the leakage current density, breakdown voltage, and trap charge density in the HfO2 film and interface of HfO2/SiC.
Bibliographical noteFunding Information:
This work was supported by National Research Foundation Grant ( NRF-2014M2B2A4030839 ) from the Ministry of Science, ICT and Future Planning (MSIP) of the Republic of Korea.
© 2017 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry