Transistor models are of utmost importance for device behaviour prediction and circuit design. Physical modelling has the advantage of the parameters being correlated based on device physics. This allows to gain insight on the device during the analysis and extraction of parameters phase. However, the extraction methods may not consider possible non-idealities of the device, which can cause modelling issues when working with novel thin film transistors (TFTs).
A simple physical DC and AC model was applied to a novel zinc tin oxide TFT annealed at low temperatures (200 ºC). The characteristic curves of four devices with different dimensions were measured and analysed, and the model parameters were extracted. The characterization and optimization of the models were implemented through the analysis of the fitting with the measured data. Two DC models were developed, the main difference being the contact resistance extraction - using the classic transmission-line method or a procedure based on MOSFETs with non-ideal behaviour that considers the possible bias dependency of the parameter. The latter method allowed to simulate the device characteristic curves more effectively. The AC model did not fit for frequencies above the cut-off and differed slightly for lower frequencies due to the simplicity of the model applied
