Self-Consistent Modeling of B or N Substitution Doped Bottom Gated Graphene FET With Nonzero Bandgap

Abstract

A phenomenological all region drain current model for boron (B) or nitrogen (N) substitution-doped bottom gated graphene field effect transistor (GFET) is developed. In this work, a self-consistent approach is utilized to obtain appropriate potential-charge relation. The effects of substitution doping such as shift in Dirac point with significant nonzero bandgap, change in carrier sheet density and mobility are explicitly captured in this model. In addition to that the semiclassical diffusive mobility is modeled extensively as a function of two predominant parameters such as interaction parameter (<inline-formula> <tex-math notation= LaTeX >${r}_{s}$ </tex-math></inline-formula>) and impurity concentration (<inline-formula> <tex-math notation= LaTeX >${n}_{i}$ </tex-math></inline-formula>). The proposed drain current model and diffusive mobility model are predicting an excellent agreement with experimental data from fabricated B-doped bottom gated GFET. B/N substitution-doped bottom gated GFETs completely suppress the bipolar behavior and exhibit significant reduction in OFF-current. And, the ON/ OFF-ratio has been enhanced significantly from 1 to <inline-formula> <tex-math notation= LaTeX >$8\\times 10^{4}$ </tex-math></inline-formula> as compared from undoped to 25% B-doped GFET, which makes B/N-doped GFETs well-suitable in digital applications. Also, B/N-doped GFETs enhance the saturation behavior which is highly desirable in analog/RF applications. Hence, B/N substitution doping in graphene fulfill the requirement of GFET in both analog/RF and digital applications.