[paper] Multi-Segment TFT Compact Model for THz Applications

Xueqing Liu¹,Trond Ytterdal² and Michael Shur^1,3

Multi-Segment TFT Compact Model for THz Applications

Nanomaterials 2022, 12(5), 765; 

DOI: 10.3390/nano12050765

  
1 RPI, Troy, NY 12180, USA
2 Norwegian University of Science and Technology, Trondheim, Norway
3 Electronics of the Future, Inc., USA

Abstract: We present an update of the Rensselaer Polytechnic Institute (RPI) thin-film transistor (TFT) compact model. The updated model implemented in Simulation Program with Integrated Circuit Emphasis (SPICE) accounts for the gate voltage-dependent channel layer thickness, enables the accurate description of the direct current (DC) characteristics, and uses channel segmentation to allow for terahertz (THz) frequency simulations. The model introduces two subthreshold ideality factors to describe the control of the gate voltage on the channel layer and its effect on the drain-to-source current and the channel capacitance. The calculated field distribution in the channel is used to evaluate the channel segment parameters including the segment impedance, kinetic inductance, and gate-to-segment capacitances. Our approach reproduces the conventional RPI TFT model at low frequencies, fits the measured current–voltage characteristics with sufficient accuracy, and extends the RPI TFT model applications into the THz frequency range. Our calculations show that a single TFT or complementary TFTs could efficiently detect the sub-terahertz and terahertz radiation.

FIG: (a) quivalent circuit of the multi-segment SPICE model for TFT and
(b) equivalent circuit for each segment including leakage components

Acknowledgements: The work was supported by Office of Naval Research (N000141712976, Project Monitor Paul Maki).