Characterization of MOS structures based on poly (3,3'''-dialkyl-quaterthiophene)

Metal-polymer-oxide-silicon (MPOS) structures with poly(3,3'''-dialkyl-quaterthiophene) as an active semiconductor layer have been characterized by means of capacitance-voltage (C-V) methods at different ramping rates (dV/dt) for the voltage sweep in the quasi-static capacitance-voltage method (QCV), and at different frequencies (f) for the dynamic or high-frequency method (DCV or HCV). The observed dependency of the capacitance on ramping rate and frequency are explained with a frequency dependent carrier enhancement and a long relaxation time constant in the polymer. The surface modification of gate oxide is found to improve the carrier enhancement in the active polymer layer of MPOS.