The Simulation Of Organic Thin-film Transistor Based On The Finite Element Method

Recently，Organic thin-film transistors have win wide attention because of thepotential of application such as electronic label, radio frequency identification cardand driver circuit of flat panel display. Compared to inorganic devices, Organicthin-film transistors have many advantages—easy availability of raw material, lowcost, light weight, simple preparation process, still they can be made into flexibledevices of large area. To sum up, the organic thin-film transistors have enormousmarket potential, wide prospect and attractive future, which will become the leadingparts of the next-generation electronic device characterized by flexibility. Therefore,it is important to study organic thin-film transistors.At present, the researches on organic thin-film transistors mainly focus onexperiments and theories. The studies on experiment have made great progress,according to report, the maximum mobility of the organic thin-film transistor hasreached35cm~2/Vs, whose active layer is pentacene of single crystal. And the studieson theory, especially for the study of working mechanism，have also made progress.The organic thin-film transistor device has been simulated on the finite elementmethod in this thesis, aiming to study the working mechanism further.The object of simulation is a organic thin-film transistor with widely usedpentacene as the active layer, which is top-gate and bottom contact geometry, andwhose carriers are holes. The simulation parameters are potential and carriersconcentration. The process is as follows: first, the physical model was established tocharacterize the device. According to the electric property of the organic materials,then the main equations applied to organic device—namely poisson equation, currentdensity equation and the continuity equation—were gained from the Maxwellequations.Subsequently, the work characteristics of organic thin-film transistor inlinear region were simulated through the established boundary conditions, and theimages of simulation results were presented. At last, the device of bottom-gate andbottom contact geometry was simulated, and the potential distributions of active layer were compared with the results measured by Kelvin Probe Force Microscopy (KPFM)method as to show that the simulation was correct.The simulation results indicate that the finite element method can be used tosimulate the organic thin-film transistor device, and it is feasible to study further theworking mechanism of organic thin film transistor through the simulation.