Electrical properties of three kinds of poly(methyl methacrylate) (PMMA) with different tacticity, i.e. isotactic(i), syndiotactic(s), and atatic(a), were investigated for the application in field effect transistor. Metal-insulator-silicon structures were fabricated via spin coating PMMA on heavily doped p-type silicon (p+-Si) followed by evaporating gold electrode. The electrical characteristics were remarkably improved by heat-treatment at temperatures 40 K above glass transition temperatures of PMMAs. Among the three PMMA isomers, i-PMMA was observed to possess the highest dielectric strength (1.1 MV/cm) with the lowest leakage current density, but also the lowest dielectric constant (k = 2.5). Top-contact thin film transistors fabricated with the configuration of NiOx/pentacene/i-PMMA/p+-Si, where the NiOx being used as a source/drain electrode, displayed relatively a decent field effect mobility of 0.042 cm2/V-s which is not that low with such a low dielectric capacitor as thick i-PMMA film.
Bibliographical noteFunding Information:
This work was supported by the Korea Research Foundation Grant (KRF-2004-042-C00047).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry