Comparative Study on Nonlinearity of Doped and Undoped GFET using DC Characteristics

Abstract

An accurate and compact mathematical model is developed to analyze the linearity and distortion performance of doped graphene field effect transistor (GFET) using dc characteristics. The proposed model is compatible with both doped GFET and undoped GFET. The vital dc figures of merit (FOMs) and metrics of linearity and distortion have been analyzed for doped GFET and compared with undoped GFET. The metrics such as second and third order transconductance terms (G m2 and G m3 ) are mathematically derived and examined to analyze the distortion behavior of the device. The fundamental FOMs such as second order input voltage intercept point (VIP 2 ), third order input voltage intercept point (VIP 3 ), and third order input intercept power (IIP 3 ) are mathematically modeled and evaluated to study the linearity behavior of the device. The interpretation of VIP 3 manifests the ability to eliminate the distortions, produced by higher order transconductance terms and identifies the starting point of distortion. The simulation results indicate that the higher order harmonics of doped GFET have been suppressed significantly and exhibits less distortion and improved linearity performance when compared to undoped GFET. Doping the graphene significantly induces bandgap in it and proves the potential of doped GFET in the requirement of highest linearity for analog/RF applications.