Unified FinFET compact model: Modelling Trapezoidal Triple-Gate FinFETs

Abstract

A unified FinFET compact model is proposed for devices with complex fin cross-sections. It is represented in a normalized form, where only four different model parameters are needed. The proposed model accurately predicts the currentvoltage characteristics of different FinFETs structures such as Double-Gate (DG), Cylindrical Gate-All-Around (Cy-GAA), or Rectangular Gate-All-Around (Re-GAA) FinFETs. In addition, for the first time, Trapezoidal Triple-Gate (T-TG) FinFETs are accurately modelled. Short-Channel-Effects (SCE) sub-models have been also implemented in the presented work. The model has been verified with TCAD data.

Core model for FinFETs

“…FinFET structures such as DG, Cy-GAA, Re-GAA, and rounded trapezoidal TG FinFETs are all modeled under the same framework. The model presented in this section has been recently being incorporated to BSIM-CMG [23]. The proposed core model can be used with shortchannel-effect submodels in a similar manner as was done in previous versions of BSIM-CMG models [27].…”

“…Several compact models have been proposed for FinFETs with complex crosssectional shapes. In this section, on the basis of the approach presented in [23], a new normalized unified FinFET core model is presented [23]. In [28], a compact model for undoped or lightly doped FinFETs was extended to model FinFETs with different crosssectional shapes by obtaining an equivalent channel thickness for each structure.…”

“…The work presented in [11] developed compact models for different shapes of undoped or lightly doped FinFETs using a combination of the compact models for DG [4] and Cy-GAA [5] FinFETs. The new normalized charge model is obtained from the solutions of Poisson's equation for DG and Cy-GAA FinFETs, which leads to a single closed-form relationship between the mobile charge and the applied terminal voltages given as follows [23]: (3.18) and q t = (q m + q dep )r N . Another compact model has recently been proposed for FinFET devices with different cross-sectional shapes [29,30], where new models for doped FinFETs were developed in a universal model framework.…”

“…(3.19) In the previous equations, v g and v ch are the normalized gate and channel potentials expressed by 3.20) and v ch = V ch v T . The normalized drain current is obtained from the solution of the Poisson-carrier transport equation [23] and is represented by It is important to notice that on the right side of Equation (3.17) there are three terms that determine the behavior of the charge in the channel: a linear term, which is important in the stronginversion region, the first logarithm term, which is important in the subthreshold region, and the last logarithm term, which is important in the moderate-inversion region.…”

Impacts of Trapezoidal Fin of 20-nm Double-Gate FinFET on the Electrical Characteristics of Circuits

“…1 [6][7][8]. Although a FinFET is believed to have uniform thickness across the height of a fin, the trapezoidal cross section has been found to be markedly different from the idealized rectangular fin body in many studies [9]. It is not clearly known whether the nonvertical cross section of the fins are manufacturing artifacts or are deliberately engineered to provide useful benefits in the chip.…”