Design and simulation of a gas sensitive junctionless FinFET based on conducting polymer as the gate material

Abstract

In this study, we demonstrate a multi-gas sensing device utilizing junctionless Fin-shaped Field Effect Transistor (FinFET) with conducting polymer as the gate material. The higher gas response is explained based on workfunction modulation of the conducting polymer gate, Poly(p-phenylene), upon gas molecule absorption. By definition, threshold voltage and off-state current variation before and after gas absorption are considered as two different measures for assessing the responsivity and sensitivity of the sensor. Basically, the main focus of this paper is designing a low power device, in which the change in the electrical characteristics of the device under gas exposure can be detected even in the absence of the gate bias. The high sensitivity of the proposed FinFET device as a gas sensor is mainly attributed to the large surface area of the 3D structure. We optimize the gas-sensing properties by investigating impact of critical physical and structural design parameters on the responsivity and selectivity of the sensor. In addition, statistical analysis is carried out to calculate coefficient of variation (CV) measure, for assessing the change in the responsivity of the gas sensor based on variation of main design parameters. Our results provide a route to design a low power CMOS compatible gas sensor that has fast response with high distinguishing selectivity and can be scaled down to nanoscale regime.