Geometry-based tunability enhancement of flexible thin-film varactors

Knobelspies, S, Gonnelli, C, Vogt, C, Daus, A, Münzenrieder, N and Tröster, G (2017) Geometry-based tunability enhancement of flexible thin-film varactors. IEEE Electron Device Letters, 38 (8). pp. 1117-1120. ISSN 0741-3106

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In this letter, flexible voltage-controlled capacitors (varactors) based on an amorphous Indium–Gallium–Zinc–Oxide (a-IGZO) semiconductor are presented. Two different varactor designs and their influence on the capacitance tuning characteristics are investigated. The first design consists of a top electrode finger structure which yields a maximum capacitance tunability of 6.9 at 10 kHz. Second, a novel interdigitated varactor structure results in a maximum tunability of 93.7 at 100 kHz. The design- and frequency-dependencies of the devices are evaluated through C–V measurements. Furthermore, we show bending stability of the devices down to a tensile radius of 6 mm without altering the performance. Finally, a varactor is combined with a thin-film resistor to demonstrate a tunable RC-circuit for impedance matching and low-pass filtering applications. The device fabrication flow and material stack are compatible with standard flexible thin-film transistor fabrication which enables parallel implementation of analog or logic circuitry and varactor devices.

Item Type: Article
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Research Centres and Groups: Sensor Technology Research Centre
Depositing User: Niko Munzenrieder
Date Deposited: 02 Aug 2017 11:22
Last Modified: 02 Jul 2019 18:51

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