Capacitance Voltage Characteristics And Capacitance Voltage Model For Thin-Film Transistors

Capacitance-voltage(CV) characteristics of thin-film transistors and a frequency-dependent CV model are investigated. First, based on the dependencies, capacitance differences between thin-film transistors(TFTs) with different layouts and the CV characteristics, the structure parameters are extracted. Then, a frequency-dependent capacitance-voltage model is developed for TFTs. The model not only includes a static CV model for channel charge analysis, a transmission line method for RC delay effect, but also includes the frequency dependent trapped charges effect on the measured capacitance. The complete model based on the same set of model parameters is verified by the measured CV characteristics of top gate self-aligned poly-Si TFTs with varied frequencies from 10 kHz to 1.5 MHz for two devices of different channel lengths, and at both room temperature and an elevated temperature of 100 °C.