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Proceedings Paper

Flexible low-voltage organic integrated circuits with megahertz switching frequencies (Presentation Recording)
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Paper Abstract

A process for the fabrication of integrated circuits based on bottom-gate, top-contact organic thin-film transistors (TFTs) with channel lengths as short as 1 µm on flexible plastic substrates has been developed. In this process, all TFT layers (gate electrodes, organic semiconductors, source/drain contacts) are patterned with the help of high-resolution silicon stencil masks, thus eliminating the need for subtractive patterning and avoiding the exposure of the organic semiconductors to potentially harmful organic solvents or resists. The TFTs employ a low-temperature-processed gate dielectric that is sufficiently thin to allow the TFTs and circuits to operate with voltages of about 3 V. Using the vacuum-deposited small-molecule organic semiconductor 2,9-didecyl-dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (C10 DNTT), TFTs with an effective field-effect mobility of 1.2 cm2/Vs, an on/off current ratio of 107, a width-normalized transconductance of 1.2 S/m (with a standard deviation of 6%), and a signal propagation delay (measured in 11-stage ring oscillators) of 420 nsec per stage at a supply voltage of 3 V have been obtained. To our knowledge, this is the first time that megahertz operation has been achieved in flexible organic transistors at supply voltages of less than 10 V. In addition to flexible ring oscillators, we have also demonstrated a 6-bit digital-to-analog converter (DAC) in a binary-weighted current-steering architecture, based on TFTs with a channel length of 4 µm and fabricated on a glass substrate. This DAC has a supply voltage of 3.3 V, a circuit area of 2.6 × 4.6 mm2, and a maximum sampling rate of 100 kS/s.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9569, Printed Memory and Circuits, 95690E (5 October 2015); doi: 10.1117/12.2187847
Show Author Affiliations
Ute Zschieschang, Max-Planck-Institut für Festkörperforschung (Germany)
Kazuo Takimiya, RIKEN Ctr. for Emergent Matter Science (Japan)
Tarek Zaki, Univ. Stuttgart (Germany)
Florian Letzkus, Institut für Mikroelektronik Stuttgart (Germany)
Harald Richter, Institut für Mikroelektronik Stuttgart (Germany)
Joachim N. Burghartz, Institut für Mikroelektronik Stuttgart (Germany)
Hagen Klauk, Max-Planck-Institut für Festkörperforschung (Germany)
Hagen Klauk, Max-Planck-Institut für Festkörperforschung (Germany)

Published in SPIE Proceedings Vol. 9569:
Printed Memory and Circuits
Emil J. W. List Kratochvil, Editor(s)

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