Electrical Characterization Measurement Of Semi-insulating SiC Single Crystal

The preparation and electronic performance of the ohmic contact electrodes were studied. Metal tantalum with 100nm thick was deposited on semi-insulating (SI) SiC single crystal doped with vanadium by sputter and annealed at 930℃in vacuum for two minutes, on which metal gold was deposited.The ohmic contact electrodes was characterized by scanning electron microscopy (SEM) and X photoelectron spectrometry (XPS). Hall Measurement was done under room temperature by Van der Pauw structure made of the ohmic contact electrodes. The capability of the ohmic contact electrodes was tested through the I-V curve. The resistivity value of SI SiC single crystal wafer measured by the Hall method was compared with that by the graphite contacts method. The value of mobility, carrier concentration gained by Hall Measurement and the formation mechanism of the ohmic contacts were also discussed.The results show the surface of the ohmic contact electrodes has a clear profile, which is composed of Ta and Si. The ohmic contacts character was proved good by the I-V measurement. The resistivity value is exact through the relationship between the temperature and Hall Measurement. The resistivity of the wafer measured by graphite contacts method was larger compared to Hall Measurement due to its hige contact resistivity. But this method can be used for rapid test of SI SiC as for its fast and nondestructive.