Alignment-free top-contact formation for organic thin film transistors with submicron-length channel

We propose a simple fabrication method for self-aligned top contacts for an organic thin film transistor (TFT) that can be miniaturized. The self-aligned top electrodes are formed without any break in the vacuum condition after the formation of an organic channel on the substrate with a prefabricated insulating structure. As a demonstration of this method, pentacene TFTs with submicron-length channels have been fabricated and successfully operated. Scanning electron microscopy of TFTs reveals well-defined TFT structures as expected.