Spin-on polymer gate dielectric for high performance organic thin film transistors

C. D. Sheraw, D. J. Gundlach, T. N. Jackson

Research output: Contribution to journalConference article

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Abstract

We have investigated the polymeric insulators benzocyclobutene (BCB), parylene C and polyimide for use as gate dielectrics in pentacene organic thin film transistors (TFTs). Atomic force microscopy (AFM) was used to examine the surface roughness of the polymeric dielectrics and the morphology of pentacene films deposited onto them. X-ray diffraction was used to examine the molecular ordering of pentacene films deposited onto the polymeric dielectrics. We find a correlation between the surface roughness of the gate dielectric and the grain size in deposited pentacene films, with smooth surfaces yielding larger, more dendritic grains. Despite significant changes in film morphology, pentacene TFTs using BCB, parylene C, or polyimide as the gate dielectric have performance comparable to device using SiO2 as the gate dielectric. These results suggest that there is not a strong correlation between pentacene film grain size and field-effect mobility for these devices. Pentacene TFTs using BCB as the gate dielectric had field-effect mobility as high as 0.7 cm2/V-s, on/off ratio > 107, subthreshold slope less than 2 V/decade, and negative threshold voltage, making them an attractive candidate for use in organic-based large-area electronic applications on flexible substrates.

Original languageEnglish (US)
Pages (from-to)403-408
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume558
StatePublished - Jan 1 2000
EventThe 1999 MRS Spring Meeting - Symposium B 'Flat-Panel Displays and Sensors-Principles, Materials and Processes' - San Francisco, CA, USA
Duration: Apr 4 1999Apr 9 1999

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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