Effect of Ti3SiC2 formation on p-type GaN by vacuum annealing on the contact properties

In the present study, after the formation of Ti3SiC2 on p-type GaN by depositing Ti-Si-C ternary film with a composition stoichiometrically close to Ti3SiC2 and subsequent annealing at temperatures of 973 K and 1073 K (lower than the annealing temperature for a contact between p-type SiC and Ti3SiC2), the resulting contact properties were analysed by X-ray diffraction, a direct-current conduction test, and a Hall-effect measurement test. The X-ray diffraction results reveal that the Ti3SiC2 phase is successfully formed after the annealing. The direct-current conduction test shows that ohmic-like contacts are achieved after the formation of Ti3SiC2. However, the Hall-effect measurement test reveals that the dominant carrier type of the specimens is inverted from p-type to n-type even after the annealing at 973 K. The N vacancy formation during the annealing is likely the cause of this change. The contact properties of the annealed specimens are discussed because it is difficult to achieve ohmic contact formation between n-type GaN and Ti3SiC2.