Effect of Adhesion Layer on Gate Insulator

The electrical performances of organic thin-film transistors (OTFTs) have been improved for the last decade. In this paper, it was demonstrated that the electrical characteristics of the organic thin film transistors (OTFTs) were improved by using polymeric material as adhesion layer on gate insulator. We have investigated OTFTs with polyimide adhesion layer which was fabricated by vapor deposition polymerization (VDP) processing and formed by co-deposition of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 4,4`-oxydianiline. It was found that the OTFTs with adhesion layer showed better electrical characteristics than with bare layer because of good matching between semiconductor and gate insulator. Our devices of performance are field effect mobility of , threshold voltage of -0.8 V and on-off current ratio of . In addition, to improve the electrical characteristics of OTFT, we have reduced the thickness of adhesion layer up to a few nanometrs.