THM-OTFT: A Complete Physics-Based Verilog-A Compact Model for Short-Channel Organic Thin-Film Transistors

Abstract

This paper presents a compact model for organic thin-film transistors fabricated in the staggered or coplanar device architecture which includes short-channel effects related to the potential barrier in the channel region, which manifest themselves as threshold voltage roll-off, drain-induced barrier lowering, and subthreshold swing degradation. Furthermore, the effect of non-linear injection due to a work-function mismatch between the source/drain contacts and the semiconductor is considered. The model includes a charge-based capacitance model considering overlap and fringing regions in short-channel multi-finger layout structures. Extensions include a model for drain-current variability, low-frequency noise and non-quasistatic effects. The introduction of physically meaningful fitting parameters provides a high degree of flexibility to the model. The equation package is verified using the results of measurements performed on transistors fabricated on flexible substrates and is available in Verilog-A for an efficient circuit simulation on different design platforms.

Keywords

• Organic semiconductor
• thin-film transistor
• compact model
• device modeling
• short channel
• capacitance