Interfacial Nanostructure and Electrical Properties of Ti₃SiC₂ Contact on p-Type Gallium Nitride

抄録

In the present study, the interfacial nanostructure and electrical properties of Ti₃SiC₂ formed by depositing a Ti–Si–C ternary film with a composition stoichiometrically equivalent to Ti₃SiC₂ on p-type GaN and subsequent annealing at 1073 K were analyzed by X-ray diffraction, transmission electron microscopy and direct current conduction test. The results reveal that structural changes occur by the annealing. Polycrystalline Ti₃SiC₂ is formed at most of the contact interface area and single crystal Ti₃SiC₂ at small area of the contact interface. Furthermore, other than Ti₃SiC₂ phase, polycrystalline Ti₅Si₃ and TiSi₂ with different grain sizes are also formed, resulting in a formation of three-layered film after the annealing. By all these structural change, the electric conduction profiles show that the Schottky barrier height (SBH) is reduced. The estimated SBH of the Ti₃SiC₂ contact on p-type GaN is 0.70 eV, which is 1.73 eV lower than the theoretically predicted value.