|
The Bi4Ti3O12 (BTO) thin film were fabricated on an n-type Si substrate and annealed by rapid thermal annealing methods. The energy distribution of interface states (Dit) and their relaxation time (τ) have been determined using the current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G/w-V) measurements of MFIS structures. The Dit of the sample determined from the high-low frequency capacitance (CHF-CLF) measurements is also presented for comparison. In addition, the C-V-f and G/w-V-f characteristics of the MFIS structures were investigated by considering series resistance (Rs) effects in a wide frequency (1 kHz-5 MHz.). The experimental C-V-f and G/w-V-f characteristics of MFIS structures show fairly large frequency dispersion especially at low frequencies due to Rs and Dit. Therefore, the high frequency capacitance (Cm) and conductance (Gm/w) values measured under both reverse and forward bias were corrected for the effect of series resistance to obtain the real capacitance of MFIS structures. The Rs-V plots exhibit anomalous peaks between inversion and depletion regions at each frequency and peak positions shift towards positive bias with increasing frequency. Also, it has been shown that the Dit decreases exponentially with increasing frequency. The C-V-f and G/w-V-f characteristics confirm that the Dit and Rs of the MFIS structures are important parameters that strongly influence the electrical properties of MFIS structures.
Keywords: MFIS structure; Admittance measurements; Frequency dependence; Interface states; Series resistance
|