Improving the Long-Term Reliability of Digital Organic Circuits (ILDOC)

• Applicants: Dr. Hagen Klauk; Professor Dr.-Ing. Yiannos Manoli
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2017 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 323274811

• Final Report Year: 2023

Final Report Abstract

Organic thin-film transistors (TFTs) are field-effect transistors in which the semiconductor is a thin layer of conjugated organic molecules. Organic TFTs can be fabricated at relatively low temperatures (below about 100 °C) and thus on unconventional substrates, such as plastics and paper. This makes organic TFTs potentially useful for mechanically flexible electronics applications, such as bendable displays and conformable sensor arrays. A critical weakness of organic TFTs is their limited stability against aging and bias stress. While the mechanisms of these effects are still under investigation, it has been found that TFTs that can be operated with lower voltages generally show better stability. Another problematic aspect of organic TFTs is that they suffer from relatively large parameter variations. Both, the poor long-term stability and the large parameter variability, create significant challenges for the efficient design of long-term-stable analog, digital and mixed-signal circuits based on organic TFTs. In this project, we made considerable progress in two critical areas related to the long-term stability of organic-TFT-based integrated circuits: We improved the TFT-fabrication process in such a way that we are now able to fabricate organic TFTs that have very large on/off current ratios even when being operated with voltages below 1 V. - We investigated a variety of novel circuit-design methodologies that lead to significantly improved long-term stability of digital organic-TFT-based circuits.

Publications

• Below-one-volt organic thin-film transistors with large on/off current ratios. Organic Electronics, 49, 179-186.
  Zschieschang, Ute; Bader, Vera Patricia & Klauk, Hagen
  
• Stable, Self-Biased and High-Gain Organic Amplifiers with Reduced Parameter Variation Effect. 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC). IEEE.
  Seifaei, Masoud; De Dorigo, Daniel; Ingvar, Fleig David; Kuhl, Matthias; Zschieschang, Ute; Klauk, Hagen & Manoli, Yiannos
  
• Achieving Ultralow Turn-On Voltages in Organic Thin-Film Transistors: Investigating Fluoroalkylphosphonic Acid Self-Assembled Monolayer Hybrid Dielectrics. ACS Applied Materials & Interfaces, 11(30), 27104-27111.
  Acharya, Rachana; Peng, Boyu; Chan, Paddy K. L.; Schmitz, Guido & Klauk, Hagen
  
• Modified Bootstrap Switching Scheme for Organic Digital Integrated Circuits. IEEE Solid-State Circuits Letters, 2(10), 219-222.
  Seifaei, Masoud; Schillinger, Daniel; Kuhl, Matthias; Keller, Matthias; Zschieschang, Ute; Klauk, Hagen & Manoli, Yiannos
  
• Flexible low-voltage high-frequency organic thin-film transistors. Science Advances, 6(21).
  Borchert, James W.; Zschieschang, Ute; Letzkus, Florian; Giorgio, Michele; Weitz, R. Thomas; Caironi, Mario; Burghartz, Joachim N.; Ludwigs, Sabine & Klauk, Hagen
  
• Nanoscale flexible organic thin-film transistors. Science Advances, 8(13).
  Zschieschang, Ute; Waizmann, Ulrike; Weis, Jürgen; Borchert, James W. & Klauk, Hagen
  
• Subthreshold Swing of 59 mV decade−1 in Nanoscale Flexible Ultralow‐Voltage Organic Transistors. Advanced Electronic Materials, 8(5).
  Geiger, Michael; Lingstädt, Robin; Wollandt, Tobias; Deuschle, Julia; Zschieschang, Ute; Letzkus, Florian; Burghartz, Joachim N.; van Aken, Peter A.; Weitz, R. Thomas & Klauk, Hagen
  
• Source-Degenerated Schmitt-Trigger-Based High-Performance Digital Logic for Flexible Organic Thin-Film Transistor Technologies.
  Seifaei, Masoud; schillinger, Daniel; Malurpatna, Prabhu Pratiksha; mohammadi, kharkeshi mohsen; Zschieschang, Ute; cuignet, xavier; Klauk, Hagen & Manoli, Yiannos