Low leakage current gate dielectrics prepared by ion beam assisted deposition for organic thin film transistors

Abstract

This communication reports on the fabrication of low operating voltage pentacene thin-film transistors with high- k gate dielectrics by ion beam assisted deposition (IBAD). These densely packed dielectric layers by IBAD show a much lower level of leakage current than those created by e -beam evaporation. These results, from the fact that those thin films deposited with low adatom mobility, have an open structure, consisting of spherical grains with pores in between, that acts as a significant path for leakage current. By contrast, our results demonstrate the potential to limit this leakage. The field effect mobility, on/off current ratio, and subthreshold slope obtained from pentacene thin-film transistors (TFTs) were 1.14 cm2 /V s, 105, and 0.41 V/dec, respectively. Thus, the high- k gate dielectrics obtained by IBAD show promise in realizing low leakage current, low voltage, and high mobility pentacene TFTs. © 2007 American Institute of Physics.