Nanoscale polymer field-effect transistors

Regioregular poly thiophene has been successfully used in large-area FET´S on account of its excellent self-assembly properties. We describe the characteristics of regioregular polythiophene FET´s with various geometry configurations and channel lengths down to 4 nm. The effects of shrinking channel length were investigated for 100 nm 40 nm channel length FET´s with source and drain patterned by a special design of large W/L ratio. Nanometer scale gaps down to 4 nm were formed by electrostatic trapping followed by electro migration processes. The impact of gap geometry was discussed. To suppress the spreading current effects, we employed a pair of guarding electrodes near the two sides of the channel which were kept at the same potential as the drain. The true responses of these nanometer scale FET´s exhibit pronounced short-channel effects due to the thick gate insulator used (100 nm) relative to the channel lengths. Our home-developed numerical model simulated the behavior of a 5 nm channel FET and reasonable agreement with the experimental data was obtained.