Electrical characterization of deposited and oxidized Ta2Si as dielectric film for SiC metal-insulator-semiconductor structures.

An alternative dielectric for MIS structures, using SiC as semiconductor, have been analysed. Ta2Si films have been deposited by direct sputtering on 6H-SiC and 4H-SiC samples, and oxidized in dry environment at 950degreesC during 90min. Ta2O5 films have been evidenced by X-Ray diffraction analysis. SIMS depth profiling analysis has revealed a considerable thickness increase of the remaining insulator after the Ta2Si oxidation, as well as the presence of an interfacial region composed by a Si-Ta-O mixture between the Ta2O5 films and the semiconductor interface. This last result has been reported in Ta2O5/Si interface previous studies. C-V and I-V measurements have been used to demonstrate the correct dielectric behaviour of the oxidized Ta2Si films, and to extract their interface properties.