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

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.