Heterogeneous Functional Dielectric Patterns for Charge‐Carrier Modulation in Ultraflexible Organic Integrated Circuits

• Published in: Advanced materials (Weinheim) Vol. 33; no. 45; pp. e2104446 - n/a
• Main Authors: Taguchi, Koki, Uemura, Takafumi, Namba, Naoko, Petritz, Andreas, Araki, Teppei, Sugiyama, Masahiro, Stadlober, Barbara, Sekitani, Tsuyoshi
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.11.2021
• Subjects: charge‐carrier modulation; Circuit reliability; Current carriers; Dicarboxylic acids; Dielectrics; Flexible components; flexible electronics; functional dielectric patterns; Integrated circuits; Materials science; Modulation; organic transistors; Oscillators; Performance measurement; polymer dielectrics; Semiconductor devices; Substrates; Threshold voltage; threshold voltage control; Transistors; Ultraviolet radiation; Wearable technology; functional dielectric patterns; integrated circuits; organic transistors; flexible electronics; charge-carrier modulation; polymer dielectrics; threshold voltage control
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202104446

Flexible electronics have gained considerable attention for application in wearable devices. Organic transistors are potential candidates to develop flexible integrated circuits (ICs). A primary technique for maximizing their reliability, gain, and operation speed is the modulation of charge‐carrier behavior in the respective transistors fabricated on the same substrate. In this work, heterogeneous functional dielectric patterns (HFDP) of ultrathin polymer gate dielectrics of poly((±)endo,exo‐bicyclo[2.2.1]hept‐ene‐2,3‐dicarboxylic acid, diphenylester) (PNDPE) are introduced. The HFDP that are obtained via the photo‐Fries rearrangement by ultraviolet radiation in the homogeneous PNDPE provide a functional area for charge‐carrier modulation. This leads to programmable threshold voltage control over a wide range (−1.5 to +0.2 V) in the transistors with a high patterning resolution, at 2 V operational voltage. The transistors also exhibit high operational stability over 140 days and under the bias‐stress duration of 1800 s. With the HFDP, the performance metrics of ICs, for example, the noise margin and gain of the zero‐VGS load inverters and the oscillation frequency of ring oscillators are improved to 80%, 1200, and 2.5 kHz, respectively, which are the highest among the previously reported zero‐VGS‐based organic circuits. The HFDP can be applied to much complex and ultraflexible ICs. Modulating the behavior of charge carriers in respective transistors on the same substrate is essential in maximizing the performance of organic integrated circuits (ICs). Heterogeneous functional dielectric patterns for charge‐carrier modulation are obtained by UV patterning. Consequently, the threshold voltage is precisely controlled within the 2–4 V operational range. Furthermore, these ultraflexible organic ICs exhibit the highest performance.