A deposited dielectric (e.g., PECVD silicon nitride) formed on an
inexpensive glass or plastic foil substrate is modified to facilitate the
formation of high mobility organic semiconductor films. In one embodiment,
the dielectric is plasma treated using nitrogen or argon gas to reduce the
surface roughness of the dielectric layer below 5 nm (peak-to-valley). An
organic semiconductor film (e.g., pentacene) grown on the modified
dielectric exhibits high mobility and large polycrystalline grain sizes.
