“…Therefore, the frequency dependent electrical characteristics are very important according to accuracy and reliable result. The characterization of interface states in MIS structure has become a subject of very intensive research in the last decade, and a number of workers have suggested various ways of characterization [5,[14][15][16][17][18][19]. The forward and reverse bias C-f and G/x-f measurements give the important information about the energy distribution of the interface states of the MIS structure.…”