Charge-Based Compact Modeling of Capacitances in Staggered Multi-Finger OTFTs

Abstract

This journal paper introduces a charge-based approach for the calculation of charges and capacitances in staggered organic thin-film transistors (OTFTs). Based on an already existing DC model, the charges are yielded in an analytical and compact form. A linear charge partitioning scheme is applied to ascribe charges to the drain/source side of the channel. The final equation is only dependent on geometrical parameters and the charge densities at the drain/source end of the channel. Furthermore, the fringing regions in fabricated devices are taken into account. The compact model is implemented in Verilog-A and the capacitances are compared to Sentaurus TCAD simulation results as well as measurement data. Additionally, simulation results for a differential amplifier are compared to measurements. The advantage of this model is its unique formulation covering all operation regimes. INDEX TERMS Capacitance, charge-based model, compact modeling, OTFT.

Advances in Compact Modeling of Organic Field-Effect Transistors

“…For instance, Leise et al [50] proposed an analytical closed-form model in the Lambert's W-function for the quasimobile charges [41]. This was further extended to account for the multi-finger contacts and fringing effects by introducing the effective channel and gate widths [51]. The model was in good agreement with experimental data in both linear and saturation regimes under quasi-static operation.…”

Simulation of Charge Carriers in Organic Electronic Devices: Methods with their Fundamentals and Applications

“…[231,233,235] For the latter reason, such models are conceived and bench-marked in a tight feedback loop with drift-diffusion-based simulations. [231,233] Typical applications comprise the determination of voltage-and frequency-dependent capacitances in transistors [231,233] and small circuits, [235] or time-dependence of charge accumulation. [231] While it appears to be straight-forward to inform the latter transistor models with more detailed drift-diffusion-based simulations, it is not established whether it is possible to rigorously extract a network of building blocks (seen above for OLEDs and transistors) from any drift-diffusion-based simulation.…”

New Compact Modeling Solutions for Organic and Amorphous Oxide TFTs

“…In [22] a charge-based capacitance model including fringing capacitances in multi-finger structures has been derived from the general charge expressions (2) or (10). The quasi-static AC model has been verified by measurements on a fabricated differential amplifier with DNTT-OTFTs on a flexible substrate and accurately models the magnitude and phase response of the circuit up to a frequency of 10 kHz.…”

“…We use the expression derived from the integration of the channel charge density in accumulation [34,41]. The expression of the drain current was not linearized (22).…”