Numerical Simulation and Investigation of Nanoscale Organic Field-Effect Transistor With Varying Channel Thickness

Abstract

Specific characteristics of organic field-effect transistors (OFETs), including channel thickness, ON-current, OFF-current, SS, threshold voltage, and turn-on voltage, are influenced by the fabrication process. The design and realization of circuits based on OFETs demand their expertise and oversight. An OFET with palladium (Pd) source/drain (S/D) electrodes, NdTaNO as dielectric material, pentacene as the active layer, and the aluminum gate electrode is simulated using Silvaco TCAD. The device's performance parameters, such as drain current, threshold voltage, current on/off ratio, transconductance, and subthreshold slope, are analyzed for varying channel thickness from 10 to 100 nm. Overall improvement in I_ON and V_TH is observed with a decrease in t_ch value. Various fabrication factors, including the management of dewetting issues, tensile strain, and compressive stress in OSC films, which are closely related to the channel thickness of the device, require careful consideration to effectively prolong the operational lifespan of OFET devices. These issues primarily arise when the thickness of the OSC is either extremely minimal or excessively large. Such extremes can result in a reduced lifespan of the device and may compromise the overall performance of the circuit. Therefore, in the analysis presented in this paper, it was discovered that the optimal device conditions and satisfactory operational behavior are achieved at thickness (t_ch) values of 60 and 50 nm. These values meet the optimal t_ch requirement for OFET fabrication.