Surface Potential-Based Analytical Modeling of Electrostatic and Transport Phenomena of GaN Nanowire Junctionless MOSFET

Abstract

This article presents a comprehensive analytical investigation of electrostatic and transport phenomena of GaN nanowire (NW) junctionless (JL) MOSFET. The evolution of the proposed model involves the solution of quasi 2-D Poisson equation with appropriate boundary conditions to obtain effective surface potential as a function of gate voltage. The mobile carrier density derived from the surface potential model is used to formulate the core transport model as well as to analyze the electrostatic characteristics for various physical device parameters. Short channel effect and certain nonideal effects including velocity saturation, mobility degradation, and channel length modulation have been incorporated in the core transport model. The impact of physical device parameters including channel length, NW radius, and oxide thickness on the performance metrics of the device such as subthreshold slope (SS), drain-induced barrier lowering (DIBL), and threshold voltage has been rigorously investigated. Upon analyzing the transport properties of the device, steep SS of 68 mV/dec, DIBL of 27 mV/V, and switching figure of merit <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$= {g}_{m}/\text {SS}$ </tex-math></inline-formula> ) of 0.16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$({\mu }\text {S}/{\mu }\text {m})/(\text {mV}/\text {dec})$ </tex-math></inline-formula> have been attained which makes the GaN NW JL MOSFET a promising candidate for emerging low-power application. The results of this work exhibit very good agreement with 3-D TCAD simulation and reported experimental results and thereby enhancing the reliability of the proposed model.