Gate dielectric surface treatment techniques for organic thin film transistor

The effects of surface treatment techniques of gate dielectric in organic thin film transistors were investigated to improve the device performances. Pentacene-based organic thin film transistors were fabricated on thermally grown SiO₂ and Argon ion and O₂ plasma treatment were performed onto SiO₂ surface to investigate their effect onto surface cleaning and subsequent device performance. X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy analyses were performed to examine the status of gate dielectric and pentacene active layer after each surface treatment, which could change the electrical performances of devices. Argon ion treated device showed a mobility 2.5 times higher than the non-treated sample and its drain current on/off ratio increased by two orders of magnitude compared to the reference non-treated sample. O₂ plasma treatment also improved the mobility, but degraded the on/off current ratio due to a high density of dangling bonds on the dielectric surface.