Characterization of Interface Traps in SiO$_2$/SiC Structures Close to the Conduction Band by Deep-Level Transient Spectroscopy

摘要

The effects of the oxidation atmosphere and crystal faces on theinterface-trap density was examined by using constant-capacitance deep-leveltransient spectroscopy to clarify the origin of them. By comparing the DLTSspectra of the low-mobility interfaces oxidized in a N$_2$O atmosphere withthose of the high-mobility interfaces on C-face oxidized in a wet atmosphere,it was found that a high density of traps are commonly observed around theenergy of 0.16 eV from the edge of the conduction band ($C1$ traps) inlow-mobility interfaces irrespective of crystal faces. It was also found thatthe generation and elimination of traps specific to crystal faces: (1) the $C1$traps can be eliminated by wet oxidation only on the C-face, and (2) the $O2$traps (0.37 eV) can be observed in the SiC/SiO$_2$ interface only on theSi-face. The generation of $O2$ traps on the Si-face and the elimination of$C1$ traps on the C-face by wet oxidation may be caused by the oxidationreaction specific to the crystal faces.