Mn-doped Ba0.6Sr0.4TiO3 high-K gate dielectrics for low voltage organic transistor on polymer substrate

Abstract

In this letter, we report on the role of Mn doping in markedly reducing leakage currents in Ba0.6Sr0.4TiO3 (BST) high-K gate dielectrics utilized in organic thin film transistors (OTFTs) fabricated on plastic substrates. Undoped and 3% Mn-doped BST thin films, deposited by rf magnetron sputtering at room temperature on Pt∕Ti∕SiO2∕Si substrates, exhibited relative dielectric constants of ∼24–28. At an applied electric field of 250kV∕cm, the 3% Mn-doped BST films exhibited leakage current densities below 2×10−8A∕cm2 compared to the much higher value of 5×10−4A∕cm2 characteristic of undoped BST films. Pentacene based OTFTs using 3% Mn-doped BST gate dielectrics exhibited low voltage operation of <10V. This demonstrates the potential use of Mn-doped BST films as high-K gate dielectrics for stable and low operating voltage OTFTs.