Evidence of Channel Mobility Anisotropy on 4H-SiC MOSFETs with Low Interface Trap Density

Abstract:

In this work, we have evaluated 4° off-axis Si face 4H-SiC MOSFETs channel performance along both the [11-20] (perpendicular to steps) and [1-100] (parallel to steps) orientations, to evidence possible anisotropy on Si-face due to roughness scattering effect. Improved gate oxide treatments, allowing low interface state densities and therefore high mobility values, have been used on both NO and N₂O annealed gate oxides. With these high channel mobility samples, a small anisotropy effect (up to 10%) can be observed at high electric fields. The anisotropy can be seen both at room and high temperatures. However, the optical phonon scattering is the dominant effect under these biasing conditions.

• Periodical: Materials Science Forum (Volume 963)
• Pages: 473-478
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.963.473
• Online since: July 2019
• Authors: Maria Cabello*, Victor Soler, Daniel Haasmann, Josep Montserrat, Jose Rebollo, Philippe Godignon
• Keywords: 4H-SiC, Mobility Anisotropy, MOSFET, Roughness Scattering

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