Understanding organic thin-film transistor fabrication based on application-relevant deposition and patterning techniques

Abstract

In this study, the focus is on understanding organic thin-film transistor fabrication based on application-relevant processing techniques like inkjet printing for deposition of the semiconductor and patterning of top-contacts using conventional photolithography and etching. A clear relation between the morphology of the semiconductor film resulting from the printing process and the measured device characteristics is found and thus a suitable thin-film transistors (TFT) design aiming at optimized electrical behavior and minimized device-to-device variations is demonstrated. We furthermore show that the organic semiconductor withstands conventional photolithography and etching on top of the polymeric film using either Ag or Au as contact material. Based on the great processing versatility of the semiconductor, short-channel bottom-gate staggered TFTs with a lowered contact resistance are demonstrated. Further improvement of the device performance is attained by optimization of the gate dielectric leading to low-voltage devices with a field-effect mobility in the range of 0.06cm 2 V -1 s -1.