Energy Band Structure of SiO2/4H-SiC Interfaces and its Modulation Induced by Intrinsic and Extrinsic Interface Charge Transfer
The energy band structure of SiO2/4H-SiC fabricated on (0001) Si- and (000-1) C-face substrates was investigated by means of synchrotron radiation x-ray photoelectron spectroscopy (SR-XPS). The band structure was found to be dependent on substrate orientation and oxide thickness due to both intrinsic and extrinsic effects that cause charge transfer at the SiO2/SiC interface. Our SR-XPS analysis revealed that the intrinsic conduction band offset of the SiO2/SiC for the C-face substrate is smaller than that for the Si-face. This means that, whereas C-face substrates exhibit high carrier mobility, a problem that is crucial to gate oxide reliability remains for SiC-based metal-oxide-semiconductor (MOS) devices owing to increased leakage current.
Edouard V. Monakhov, Tamás Hornos and Bengt. G. Svensson
H. Watanabe et al., "Energy Band Structure of SiO2/4H-SiC Interfaces and its Modulation Induced by Intrinsic and Extrinsic Interface Charge Transfer", Materials Science Forum, Vols. 679-680, pp. 386-389, 2011