Analytic potential and charge model for III-V surrounding gate metal-oxide-semiconductor field-effect transistors

Abstract

In this work, an analytical model is proposed to calculate the potential and the inversion charge of III-V cylindrical Surrounding-Gate metal-oxide-semiconductor field-effect transistors (MOSFETs). The model provides expressions for the calculation of the subband energies and their corresponding wavefunctions, taking into account their penetration into the gate insulator and the effective mass discontinuity in the semiconductor-insulator interface for this kind of devices. The model considers Fermi-Dirac statistics and the two-dimensional quantum confinement of the carriers. We demonstrate that our analytical solution fits very well the numerical solution in all operating regimes and for different device sizes and materials.

Analytic drain current model for III–V cylindrical nanowire transistors

“…9 (2) It accounts for the electron quantum nature (observed in small NWs 10,11 ) avoiding classical depictions [12][13][14][15] of the charge. For this, we extend the results of a Q-V model presented in a previous work 16 (by successfully solving the Schr€ odinger and Poisson equations for an arbitrary number of subbands).…”

“…16, where we analytically solved the Schr€ odinger and Poisson equations for the 2D cross section of a cylindrical III-V NW by considering the C-valley of the conduction band. Fig.…”

“…In Ref. 16, we took into account the wavefunction penetration into the gate insulator and the effective mass discontinuity in the semiconductor-insulator interface to obtain a solution of the Schr€ odinger equation for an arbitrary number of energy subbands. However, the solution for the Poisson equation was restricted to the first three subbands.…”

“…In Section II, we present the solutions of the Schr€ odinger and Poisson equations for an arbitrary number of subbands. 16 In Section III, we determine the drain current expression using the gradual channel approximation (GCA). In Section IV, we validate the numerical simulator (which we later use to check the model) against experimental results obtained from the literature.…”

Compact modeling of subthreshold swing in double gate and nanowire MOSFETs, for Si and GaAs channel materials

“…It is therefore unable to reproduce this ''ringing''. Another specific feature of 2D confined III-V structures such as GaAs NW MOS is that the gate capacitance may decrease with V g [36,37]. Indeed, due to the reduced density of state (DOS) of III-V materials, the inversion charge in the C valley is unable to pin the potential at the bottom of the conduction band as it does in Si.…”