Observations of very fast electron traps at SiC/high-κ dielectric interfaces
Arnar M. Vidarsson,
Axel R. Persson,
Jr-Tai Chen,
Daniel Haasmann,
Jawad Ul Hassan,
Sima Dimitrijev,
Niklas Rorsman,
Vanya Darakchieva,
Einar Ö. Sveinbjörnsson
Affiliations
Arnar M. Vidarsson
Science Institute, University of Iceland, IS-107 Reykjavik, Iceland
Axel R. Persson
Department of Physics, Chemistry and Biology (IFM), Competence Centre for III-Nitride Technology C3NiT-Janzén, Linköping University, SE-581 83 Linköping, Sweden
Jr-Tai Chen
Department of Physics, Chemistry and Biology (IFM), Competence Centre for III-Nitride Technology C3NiT-Janzén, Linköping University, SE-581 83 Linköping, Sweden
Daniel Haasmann
Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia
Jawad Ul Hassan
Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
Sima Dimitrijev
Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia
Niklas Rorsman
Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
Vanya Darakchieva
Department of Physics, Chemistry and Biology (IFM), Competence Centre for III-Nitride Technology C3NiT-Janzén, Linköping University, SE-581 83 Linköping, Sweden
Einar Ö. Sveinbjörnsson
Science Institute, University of Iceland, IS-107 Reykjavik, Iceland
Very fast interface traps have recently been suggested to be the main cause behind poor channel-carrier mobility in SiC metal–oxide–semiconductor field effect transistors. It has been hypothesized that the NI traps are defects located inside the SiO2 dielectric with energy levels close to the SiC conduction band edge and the observed conductance spectroscopy signal is a result of electron tunneling to and from these defects. Using aluminum nitride and aluminum oxide as gate dielectrics instead of SiO2, we detect NI traps at these SiC/dielectric interfaces as well. A detailed investigation of the NI trap density and behavior as a function of temperature is presented and discussed. Advanced scanning transmission electron microscopy in combination with electron energy loss spectroscopy reveals no SiO2 at the interfaces. This strongly suggests that the NI traps are related to the surface region of the SiC rather than being a property of the gate dielectric.
