Compact Modeling of Short-Channel Effects in Staggered Organic Thin-Film Transistors

• Published in: IEEE transactions on electron devices Vol. 67; no. 11; pp. 5082 - 5090
• Main Authors: Pruefer, Jakob, Leise, Jakob, Darbandy, Ghader, Nikolaou, Aristeidis, Klauk, Hagen, Borchert, James W., Iniguez, Benjamin, Gneiting, Thomas, Kloes, Alexander
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 2-D potential solution; compact modeling; Coordinates; Current voltage characteristics; drain-induced barrier lowering (DIBL); Electric potential; Geometry; Logic gates; Mathematical analysis; Mathematical model; organic thin-film transistors (TFTs); Semiconductor devices; short-channel effects; Solid modeling; Substrates; Thin film transistors; threshold-voltage shift; Transistors; Two dimensional analysis
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2020.3021368

This article introduces analytical compact models of short-channel effects in staggered organic thin-film transistors (TFTs). The effects of subthreshold-swing degradation, threshold-voltage roll-off, and drain-induced barrier lowering (DIBL) on the static current-voltage characteristics of staggered TFTs are extracted from an analytical potential solution of the 2-D problem of the staggered geometry. This solution is derived by using the Schwarz-Christoffel transformation that leads to a complex mapping function linking the staggered geometry to an equivalent in another coordinate system for which an analytical potential solution exists. The technology CAD (TCAD) Software Sentaurus is used to verify the compact models. Finally, the closed-form and physics-based equations are incorporated into an existing compact current model and verified by measurements on staggered organic TFTs with channel lengths as small as 0.4 <inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> fabricated on flexible plastic substrates by stencil lithography.