Thermal stability of organic thin-film transistors with self-assembled monolayer dielectrics

We have investigated the annealing effects on 2 V-operation pentacene organic thin-film transistors (TFTs) with self-assembled monolayer-based gate dielectrics. When pentacene TFTs without passivation layers are annealed at 100 degrees C, the pentacene crystal structure changes to the bulk phase, resulting in an irreversible degradation of electronic performances. This degradation is suppressed by a 2.5-mu m-thick passivation layer. The mobility of the encapsulated TFTs decreases by only 12% upon annealing at 140 degrees C. We have also investigated the bias-stress effect and found the drain current of low-voltage pentacene TFTs annealed at 70 degrees C decreases by 1% during continuous bias stress for 1 h.