Electrostatic characterization and threshold voltage modeling of inversion type InGaAs gate-all-around MOSFET

• Published in: Journal of computational electronics Vol. 20; no. 4; pp. 1504 - 1512
• Main Authors: Rahman, I. K. M. Reaz, Khan, Md. Irfan, Khosru, Quazi D. M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2021; Springer Nature B.V
• Subjects: Approximation; Boundary conditions; Charge density; Electric fields; Electrical Engineering; Electrons; Electrostatics; Engineering; Indium gallium arsenides; Material properties; Mathematical and Computational Engineering; Mathematical and Computational Physics; Mechanical Engineering; MOSFETs; Nanowires; Optical and Electronic Materials; Physical properties; Poisson equation; Silicon; Theoretical; Threshold voltage; Transistors; Lambert function; Capacitance-voltage characteristics; Gate-all-around; Volume inversion; Electrostatic charge
• ISSN: 1569-8025; 1572-8137
• DOI: 10.1007/s10825-021-01716-5

This paper presents an analytical investigation of the electrostatic properties of a moderately doped symmetric gate-all-around nanowire MOSFET having InGaAs channel. The model is continuous from depletion to strong inversion regime that circumvents regional approach, thus smoothly capturing the transition of the charge profile in all regions of operation. The evolution of the model is facilitated by the solution of quasi 2-D Poisson equation with appropriate boundary conditions in a square gate-all-around geometry, incorporating fixed oxide charge and interface trap defects. The determination of mobile charge density leads to the capacitance-voltage (CV) characteristics as a function of gate bias. The CV profile is investigated subject to scaling of physical parameters and material properties. Further, a threshold voltage model is presented for a long channel gate-all-around device that utilizes the well-known double derivative method. This model accurately predicts the threshold voltage variation with fin width, oxide thickness and channel doping, highlighting room for further improvement in electrostatics by incorporating high-k dielectric. The excellent match between the model results and TCAD simulation reflects the validity of the proposed model.