Effect of post metallization annealing on the electrical characteristics of Pd/HfO2/6H-SiC MIS capacitors and extraction of conduction mechanisms

Effect of post metallization annealing on the electrical characteristics of Pd/HfO
₂
/6H-SiC MIS capacitors are reported in this work. MIS capacitors when subjected to post metallization annealing in forming gas for longer duration (40 min) exhibited improved electrical characteristics. Density of interface states is found to be reduced by one order. Gate leakage current density is also reduced for the devices when compared with those MIS capacitors for which annealing was carried out for only 10 minutes. Minimum value of interface state density is extracted to be 6.5 ×10
¹⁰
/cm
²
eV and gate leakage current density of 0.47 A/cm
²
is obtained at an electric field of 5 MV/cm in devices which have undergone annealing for extended duration. Conduction mechanisms contributing to leakage current in the entire range of gate electric field are also extracted and presented in this paper. Major mechanism of conduction at low electric field is determined to be Trap assisted tunneling, while Fowler-Nordheim tunneling is dominating at high electric field.