An Investigation of Capacitance-Voltage Hysteresis in Al₂O₃/SiC MIS Capacitors

E-ISSN： 1662-9752|2015|821|516-519

ISSN： 0255-5476

Source： Materials Science Forum, Vol.2015, Iss.821, 2015-07, pp. : 516-519

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Abstract

Charge trapping behavior in Al₂O₃/SiC MOS structures was investigated by C-V hysteresis measurements in combination with XPS analysis. According to the quadratic fit of C-V hysteresis vs. t_ox curves, the density of the injected charges in the bulk Al₂O₃ films are the same under different maximum electric field, while the density of sheet charges increase with the increase of maximum electric field. Thus, a simple sheet charge model has been used to evaluate the actual effect of the electron injection phenomenon. The charge trapping levels can be as high as 10¹³ cm^-2, indicating the importance of C-V hysteresis in Al₂O₃/SiC structures. All the trapping charges are found to be located at a distance ranging from 3 to 4 nm from the interface. Furthermore, no detectable interface oxide between Al₂O₃ and SiC has been found through our XPS measurements. We conclude that the origin of charge trapping sites in Al₂O₃/SiC structures is the native defects in ALD Al₂O₃ layer and predominantly the border traps in the Al₂O₃ near the oxide/semiconductor interface.