The effects of surface treatment on device performance in pentacene-based thin film transistor

We report on the influence of surface treatment using hexamethyldisilazane (HMDS) on device performance of pentacene-based thin film transistor. The samples with surface treatment using HMDS show higher mobility, lower subthreshold slope, and lower off-current compared to the untreated samples. We have also investigated the effect of various coating methods of HMDS on device performance. In the case of post-baked samples after spin coating, the improvements of mobility and on-current are larger than those of spin-coated samples. Especially a dip-coated sample has threshold voltage of −4.11 V and turn-on voltage of −0.03 V, showing the enhancement mode characteristics, which is useful for the operation as a circuit and a switch device for active-matrix displays. However, the mobility of dip-coated sample is one order lower than that of spin-coated sample, and hysteresis is larger than that of spin-coated sample.