Impact of contact and channel resistance on the frequency-dependent capacitance and conductance of pseudo-MOSFET

This paper discusses the impact of both contact and channel resistance on capacitance and conductance characteristics measured with pseudo-MOSFET method by analyzing the impedance and admittance in frequency domain. We clarify the mechanisms affecting the ac response of pseudo-MOSFET structure for SOI wafer with thin SOI film by using simple series and parallel circuits composed of resistance and capacitance. Our measurement results show the gate bias range where the influence of the contact resistance becomes dominant in measurements with single and multiple probes. The degradation of the capacitance measured at high frequency is also analyzed by constructing an equivalent circuit, which detach the influence of the contact and channel resistances quantitatively. The necessity to carefully account for the influence of the contact resistance in pseudo-MOS method is clarified.