The effect of indirect UV/ozone treatment on pentacene thin film transistors with double-stacked organic gate insulators

Abstract

We investigated the indirect UV/ozone treatment, which means treating the insulator surface under tens of nanometers, rather than the direct surface of the insulator. The double-stacked organic layers are used as gate insulator and the UV/ozone treatment is conducted between these two layers. We analyzed the surface morphologies of the gate insulator and the pentacene by atomic force microscopy (AFM) to confirm the effect of indirect UV/ozone treatment. The UV/ozone treatment reduced the surface roughness of the upper side gate insulator and increased the pentacene grain size. Pentacene-based thin film transistors were fabricated and the electrical property improvement after this treatment was examined. The largest improvement was found when the UV/ozone treatment time is 10 min and the upper side gate insulator thickness is 20 nm, and the mobility at that condition is 1.21 cm(2)/V s, which is larger than three times that without UV/ozone treatment (0.33 cm(2)/V s).