On the Origin of Threshold Voltage Instability under Operating Conditions of 4H-SiC n-Channel MOSFETs
We report on the threshold voltage () instability under operating conditions after gate bias switches at constant drain voltage for n-MOSFETs fabricated on 4H silicon carbide (4H-SiC). This effect occurs at room temperature and close to the of the device. We show that the origin of the instability is electron trapping into SiO2 over an energy barrier of (0.3-0.4) eV. These traps show similarities to traps previously observed in 4H-SiC MOS capacitors and labelled near interface traps (NITs). Further, the density of the traps can be reduced by one order of magnitude through post-oxidation annealing in nitric oxide atmosphere.
Fabrizio Roccaforte, Francesco La Via, Roberta Nipoti, Danilo Crippa, Filippo Giannazzo and Mario Saggio
G. Pobegen et al., "On the Origin of Threshold Voltage Instability under Operating Conditions of 4H-SiC n-Channel MOSFETs", Materials Science Forum, Vol. 858, pp. 473-476, 2016