윤준식 교수

In this paper, we systematically evaluate dc/ac performances of sub-7-nm node fin field-effect transistors (FinFETs) and nanosheet FETs (NSFETs) using fully calibrated 3-D TCAD. The stress effects of all the devices were carefully considered in terms of carrier mobility and velocity averaged within the active regions. For detailed AC analysis, the parasitic capacitances were extracted and decomposed into several components using TCAD RF simulation platform. FinFETs improved the gate electrostati

In this paper, multi-threshold voltage ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> ) scheme of 7-nm node nanosheet FETs (NSFETs) with narrow NS spacing were successfully achieved by metal-gate work function (WF) and channel doping ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> <sub xm

Analog/RF performances of 5-nm node bulk fin-shaped field-effect transistors (FinFETs) and nanosheet FETs (NSFETs) were investigated and compared thoroughly using fully-calibrated TCAD. NSFETs have greater current drivability and gate-to-channel controllability than FinFETs under the same footprint, thus achieving larger intrinsic gain. But the cutoff frequencies (F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> ) of FinFETs and NSFETs are

Process (systematic) variations of sub-5-nm node fin field-effect transistors (FinFETs) and nanosheet field-effect transistors (NSFETs) were investigated thoroughly using fully calibrated TCAD. All the process parameters consisting of front-endas well as middle-of-line structure were independently randomized within feasible process conditions. A novel process scheme called source/drain patterning (SDP), having a superior performance by decreasing outer fringing capacitance through the downsized

DC/AC characteristics of Si bulk FinFETs including middle-of-line levels are precisely investigated using well-calibrated 3-D device simulations for system-on-chip applications. Scaling the fin widths down to 5 nm effectively enhances gate-to-channel controllability and improves RC delay, but a dramatic increase in band-to-band tunneling currents from source-to-drain does not satisfy low-power application in the 7-nm node. All lightly-doped extension regions as a solution could improve band-to-b

Structural advancements of 5-nm node bulk fin-shaped field-effect transistors (FinFETs) without punch-through-stopper (PTS) were introduced using fully calibrated TCAD for the first time. It is challenging to scale down conventional bulk FinFETs into 5-nm technology node due to the sub-fin leakage increase. Meanwhile, bottom oxide deposition after anisotropic etching for source/drain (S/D) epi formation prevents the sub-fin leakage effectively even without the PTS doping, thus achieving better g

Vertical gate-all-around (GAA) junctionless nanowire transistors (JNTs) with different diameters and underlap lengths are investigated using three-dimensional device simulations. The source-side diameter determines the on-current and drain-induced barrier lowering characteristics, whereas the drain-side diameter controls the band-to-band tunneling current during off-state conditions. The JNTs with short drain-side underlap lengths decrease the source/drain series resistance but increase the off-

Random dopant fluctuation effects of gate-all-around inversion-mode silicon nanowire field-effect transistors (FETs) with different diameters and extension lengths are investigated. The nanowire FETs with smaller diameter and longer extension length reduce average values and variations of subthreshold swing and drain-induced barrier lowering, thus improving short channel immunity. Relative variations of the drain currents increase as the diameter decreases because of decreased current drivabilit

Source/drain (S/D) variations in sub-5-nm node fin and nanosheet field-effect transistors (NSFETs) were thoroughly analyzed by using fully calibrated technology computer-aided design (TCAD). S/D open and contact critical dimensions (OCD and CCD) vary during anisotropic etching for silicide and S/D epi formations, respectively, and these vary dc/ac performances. OCD varies S/D resistances and parasitic capacitances, but slight RC delay variations occur. CCD affects OFF-state currents (IOFF) and R

Sub-7-nm node nanosheet field-effect transistors adopting metal source/drain (S/D) structure were analyzed in depth using fully calibrated TCAD. Metal S/D structure was formed by anisotropic etching of low- ${k}$ and S/D epi regions followed by metal-line (M0) deposition without additional mask under conventional CMOS process. Larger S/D metal depth increases the contact area between S/D epi and M0, thus increasing current drivability greatly without decreasing contact resistivity. A slight ac p

DC/AC performance and the variations due to single interface trap of the nanowire (NW) FETs were investigated in the 7-nm technology node using fully calibrated TCAD simulation. Shorter junction gradient and greater diameter reduced RC delay without short channel degradations. Spacer with smaller dielectric constants decreased parasitic and gate capacitances with a slight decrease of ON-state currents, thus minimizing RC delay. Interface traps for the variability analysis were P <sub xmlns:mml="

Structural modifications of 5-nm node nanosheet FETs (NSFETs) were quantitatively analyzed using fully calibrated TCAD. The NSFETs with crescent inner spacer improve the short-channel effects by increasing effective gate lengths but also increase the parasitic capacitances by greater outer fringing electric field. The NSFETs with a crescent inner spacer and slanted source/drain (S/D) increase the physical gate lengths of bottom NS channel, but the anisotropic over-etching of substrate regions in

Abstract The DC/AC performances of sub-7-nm node nanosheet FETs (NSFETs) with different NS widths ( W NS ) and number of NSs ( N NS ) were investigated after fine calibration to 10-nm node fin-shaped FETs (FinFETs). A smaller W NS improves the short-channel effects but decreases the effective widths and the on-state currents ( I on ). A higher N NS is beneficial for improving I on by reducing source/drain (S/D) resistance, but longer carrier paths for the NS channels far from the S/D contacts ac

Vertical nanowire field-effect transistors (NWFETs) have been optimized to maximize digital and analog performances using fully-calibrated TCAD and machine learning (ML) technique. Digital performance is quantified by RC delay (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gg</sub> V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dd</sub> /I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns

We analyzed the performance, power, area of 3 nm node fin and nanosheet (NS) field-effect transistors (FETs) implementing buried power rail (BPR) after full calibration to 5 nm node hardware. Fin-shaped FETs (FinFETs) have smaller <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> delay than do NS FETs (NSFETs) under the same footprint and two-fin configuration. Larger number of NS channels boost drive currents but also increase gate capacita