Investigation of electrical properties of P-type 6H-SiC bulk crystal

6H-SiC single crystals with different aluminum doping concentrations were grown by physical vapor transport (PVT) method. Al₂O₃ powder was used as Al source during the growth and was put into a small crucible to avoid the rapid depletion of aluminum source. The incorporation of Al atoms and electrical properties of p-type 6H-SiC were characterized by secondary ion mass spectroscopy (SIMS) and Hall measurements in Van-der-Pauw configuration, respectively. Results showed that the maximum hole concentration in aluminum concentration of 4×10¹⁸ cm^-3 was 1.3×1017 cm^-3 with Hall mobility of 24.8 cm²/V·S and resistivity of 1.89 Ω·cm. The resistivities of samples were investigated in detail by a noncontact resistivity testing system and an innovative contactless resistivity measurement system at room temperature. Results showed that the minimum resistivity of 855 mΩ·cm was obtained at the center region of one wafer with the aluminum content of 4×10¹⁸ cm^-3. In addition, the resistivity distributions along the growth direction and the radial direction were discussed.