A multi-nanosheet field-effect transistor (mNS-FET) device was developed to maximize gate controllability while making the channel in the form of a sheet. The mNS-FET has superior gate controllability for the stacked channels; consequently, it can significantly reduce the short-channel effect (SCE); however, punch-through inevitably occurs in the bottom channel portion that is not surrounded by gates, resulting in a large leakage current. Moreover, as the size of the semiconductor device decreases to several nanometers, the influence of the parasitic resistance and parasitic capacitance increases. Therefore, it is essential to apply design–technology co-optimization, which analyzes not only the characteristics from the perspective of the device but also the performance from the circuit perspective. In this study, we used Technology Computer Aided Design (TCAD) simulation to analyze the characteristics of the device and directly fabricated a model that describes the current–voltage and gate capacitance characteristics of the device by using Berkeley short-channel insulated-gate field-effect transistor–common multi-gate (BSIM–CMG) parameters. Through this model, we completed the Simulation Program with Integrated Circuit Emphasis (SPICE) simulation for circuit analysis and analyzed it from the viewpoint of devices and circuits. When comparing the characteristics according to the presence or absence of bottom oxide by conducting the above research method, it was confirmed that subthreshold slope (SS) and drain-induced barrier lowering (DIBL) are improved, and power and performance in circuit characteristics are increased.

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Poly-crystalline silicon channel transistors have been used as a display TFT for a long time and have recently been used in a 3D vertical NAND Flash which is a transistor with 2D plane NAND upright. In addition, multi-gate transistors such as FinFETs and a gate-all-around (GAA) structure has been used to suppress the short-channel effects for logic/analog and memory applications. Compact models for poly-crystalline silicon (poly-silicon) channel planar TFTs and single crystalline silicon channel GAA MOSFETs have been developed separately, however, there are few models consider these two physics at the same time. In this work, we derived new analytical current-voltage model for GAA transistor with poly-silicon channel by considering the cylindrical coordinates and the grain boundary effect. Based on the derived formula, the compact I-V model for various operating regions and threshold voltage was proposed for the first time. The proposed model was compared with the measured data and good agreements were observed.

Recently, in accordance with the demand for development of low-power semiconductor devices, a negative capacitance field-effect-transistor (NC-FET) that integrates ferroelectric material into a gate stack and utilizes negative capacitive behavior has been widely investigated. Furthermore, gate-all-around (GAA) architecture to reduce short-channel effect is expected to be applied after Fin-FET technology. In this work, we proposed a compact model describing current–voltage (I–V) relationships of an NC GAA-FET with interface trap effects for the first time, which is a simplified model by taking proper approximation in each operating region. This is a surface potential-based compact model, which is suitable for evaluating the I–V characteristics for each operating region. It was validated that the proposed model shows good agreement with the results of implicit numerical calculations. In addition, by using the proposed model, we explored the electrical properties of the NC GAA-FET by varying the basic design parameters such as ferroelectric thickness (tfe), intermediate insulator thickness (tox), silicon channel radius (R), and interface trap densities (Net).

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