Analytical modeling of contact resistance in organic transistors

Organic thin film transistors (OTFTs) are of significant interest for the development of organic electronics. The devices described in this paper, through measurements, analytic extraction of parameters and simulations, are organic transistor having Polytriarylamine (PTAA) as semiconductor. This paper refers to the determination of the source and drain contact resistance of these PTAA organic transistors. The MATLAB Simulink model is based on an analytic model, for which DC Sweep and parametric simulations were employed in order to obtain the total resistance. The results are processed in accordance to the Transfer Line Method (TLM). This mathematical method uses results on the total channel resistance of the thin film transistors with various channel lengths in order to extrapolate the contact resistance. The TLM structures considered here are bottom contact top gate OTFTs with interdigitated electrodes of various channel lengths. The values of the contact resistance are considered equal due to the symmetry of the measured structure.