Observation and Modelling of the Gate-Source Capacitance Overshoot in Polysilicon TFTs

摘要

A high sensitivity system has been set-up for the measurement of inter-nodal C-V characteristics in MOSFET devices at low frequencies (20 Hz to 100 kHz). Its application to the measurement of gate to source capacitance of polysilicon thin film transistors (poly-Si TFTs) reveals for the first time the presence of a peak exceeding the oxide capacitance at very low frequencies. This and other experimentally observed features are explained by a new analytical model requiring only the knowledge of the device channel conductance.