Poly-p-xylylene derivatives as non-solution processible gate dielectric materials for organic field effect transistor

Abstract

A flexible insulator film would be one of the most important elements of flexible organic field-effect transistors (OFETs). It should be produced from a soft organic material rather than a stiff inorganic material. Many polymeric materials were spin-coated from the solution and the resulted films have to be baked or cured to obtain a good insulator. Since those procedures impose a restriction on the OFETs, a fabrication process without using a solvent has been desired. Poly-p-xylylene derivatives have been made into an insulator film by a non-solvent procedure, chemical vapor deposition (CVD). The insulator film has additional advantages, pinhole-free, resistance to many solvents and no thermal stress to a material beneath. We have fabricated and characterized OFETs with the inverted staggered geometry, substrate/ gate electrode/ poly-p-xylylene derivatives/ organic semiconductor/ source-drain electrodes. And the CVD enables to form an insulator film even above the organic semiconductor. So we fabricated the staggered type configuration, substrate/ source-drain electrodes/ organic semiconductor/ poly-chloro-p-xylylene/ gate electrode. The device performance of a staggered type transistor indicated that the molecular arrangement of organic semiconductor at the insulator interface is more dominant than the damage or chemical deterioration due to the attack of the radicals during the CVD procedure.