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Woo Young Choi

Seoul National University · Engineering

About the Lab

Professor Woo Young Choi's research lab specializes in next-generation semiconductor devices, focusing on low-power and high-performance transistors for advanced integrated circuits. The lab pioneers innovations in tunneling field-effect transistors (TFETs) and I-MOS (Independent Gate MOS) devices, aiming to overcome the limitations of conventional MOSFETs, particularly subthreshold swing and power consumption. Their work emphasizes novel device structures, advanced fabrication processes, and integration techniques for nanoscale CMOS-compatible technologies. The lab also explores electro-mechanical non-volatile memory devices for embedded memory applications.

TFETI-MOSlow-power devicesnanoscale integrationnon-volatile memory

Research Overview

Papers
323
Total Citations
5,755
Papers (5y)
100
Primary Field
Engineering

Research Output Trend

Figures are computed from collected data and may differ slightly.

Publications per year (5y)
100total
2022
2023
2024
2025
2026
Citations per year (5y)
539total
20222023202420252026

Selected Papers

15
1
Article|1,891 citations·2007
Tunneling Field-Effect Transistors (TFETs) With Subthreshold Swing (SS) Less Than 60 mV/dec
Woo Young Choi, Byung‐Gook Park, Jong Duk Lee, Tsu‐Jae King Liu
SJR Q1IEEE Electron Device Letters

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We have demonstrated a 70-nm n-channel tunneling field-effect transistor (TFET) which has a subthreshold swing (SS) of 52.8 mV/dec at room temperature. It is the first experimental result that shows a sub-60-mV/dec SS in the silicon-based TFETs. Based on simulation results, the gate oxide and silicon-on-insulator layer thicknesses were scaled down to 2 and 70 nm, respectively. However, the <emphasis

Electrical and Electronic EngineeringEngineering
2
Article|475 citations·2010
Hetero-Gate-Dielectric Tunneling Field-Effect Transistors
Woo Young Choi, Woojun Lee
SJR Q2IEEE Transactions on Electron Devices

A tunneling field-effect transistor (TFET) is considered one of the most promising alternatives to a metal–oxide–semiconductor field-effect transistor due to its immunity to short-channel effects. However, TFETs have suffered from low <emphasis emphasistype="smcaps" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</emphasis> -current, severe ambipolar behavior, and gradual transition between <emphasis emphasistype="smcaps" xmlns:mml="http://www.w3.org/

Electrical and Electronic EngineeringEngineering
3
Article|98 citations·2011
Analytical model of single-gate silicon-on-insulator (SOI) tunneling field-effect transistors (TFETs)
Min Jin Lee, Woo Young Choi
SJR Q3Solid-State Electronics
Electrical and Electronic EngineeringEngineering
4
Article|80 citations·2005
100-nm n-/p-channel I-MOS using a novel self-aligned structure
Woo Young Choi, Jae Young Song, Jong Duk Lee, Young June Park, Byung‐Gook Park
SJR Q1IEEE Electron Device Letters

We have fabricated a 100-nm n-/p-channel I-MOS by adopting a novel structure. The proposed structure shows some advantages over the conventional one in terms of self-alignment and reduced number of photolithography masks. It leads to low fabrication cost, accelerated scaling down, and enhanced performance due to reduced parasitic elements. It shows a normal transistor operation with small subthreshold swing less than 11.8 mV/dec at room temperature. The n- and p-channel I-MOS have an ON/OFF curr

Electrical and Electronic EngineeringEngineering
5
Article|79 citations·2005
70-nm impact-ionization metal-oxide-semiconductor (I-MOS) devices integrated with tunneling field-effect transistors (TFETs)
Woo Young Choi, Jae Young Song, Jong Duk Lee, Young June Park, Byung‐Gook Park

70-nm I-MOS devices have been integrated with 70-nm TFETs for the first time by adopting a novel process method. The integration of the I-MOS device with the TFET is meaningful in that it compensates for weak points of each device and implements both high-performance and low-power functionality on the same substrate. Additionally, by using SOI substrate and modifying mask layout, ON/OFF current ratio of the I-MOS device is increased dramatically by a factor of more than 1000 compared with our pr

Electrical and Electronic EngineeringEngineering
6
Article|68 citations·2016
Demonstration of hetero-gate-dielectric tunneling field-effect transistors (HG TFETs)
Woo Young Choi, Hyunkook Lee
SJR Q1Nano ConvergenceOA

The steady scaling-down of semiconductor device for improving performance has been the most important issue among researchers. Recently, as low-power consumption becomes one of the most important requirements, there have been many researches about novel devices for low-power consumption. Though scaling supply voltage is the most effective way for low-power consumption, performance degradation is occurred for metal–oxide–semiconductor field-effect transistors (MOSFETs) when supply voltage is redu

Electrical and Electronic EngineeringEngineering
7
Article|59 citations·2023
Synaptic Characteristics and Vector‐Matrix Multiplication Operation in Highly Uniform and Cost‐Effective Four‐Layer Vertical RRAM Array
Jihyung Kim, Subaek Lee, Sungjoon Kim, Sungjoon Kim, Seyoung Yang, Jung‐Kyu Lee, Tae‐Hyeon Kim, Muhammad Ismail, Chandreswar Mahata, Yoon Kim, Woo Young Choi, Sungjun Kim
SJR Q1Advanced Functional Materials

Abstract This study implements a highly uniform 3D vertically stack resistive random‐access memory (VRRAM) with a four‐layer contact hole structure. The fabrication process of a four‐layer VRRAM is demonstrated, and its physical and electrical properties are thoroughly examined. X‐ray photoelectron spectroscopy and transmission electron microscopy are employed to analyze the chemical distribution and physical structure of the VRRAM device. Multilevel capability, reliable endurance (&gt;10 4 cycl

Electrical and Electronic EngineeringEngineering
8
Article|58 citations·2007
Compact Nano-Electro-Mechanical Non-Volatile Memory (NEMory) for 3D Integration
Woo Young Choi, Hei Kam, Donovan Lee, Joanna Lai, Tsu‐Jae King Liu

A new electro-mechanical non-volatile memory (NVM) cell design is proposed and demonstrated for the first time. The fabricated cells operate with relatively low program/erase voltages and large sensing margin. Because only dielectric and metal layers are required, this cell design is suitable for post-CMOS fabrication. As the cell area is reduced, low operating voltages can be maintained by scaling the vertical dimensions of the cell. Nanometer-scale electro-mechanical memory technology is there

Electrical and Electronic EngineeringEngineering
9
Article|50 citations·2005
A novel biasing scheme for I-MOS (impact-ionization MOS) devices
Woo Young Choi, Jae Young Song, Jong Duk Lee, Y.J. Park, Byung-Gook Park
SJR Q2IEEE Transactions on Nanotechnology

A novel biasing scheme for impact-ionization metal-oxide semiconductor (I-MOS) devices was proposed based on the physics of the device, which features negative biasing at the source region. To confirm the proposed idea, we have simulated an I-MOS whose gate length is 130 nm. According to the simulation results, by increasing the value of the reverse source-to-body bias, we can enhance the electrical characteristics of I-MOS devices. With the source bias of -6.5 V, a 130-nm I-MOS has a threshold

Electrical and Electronic EngineeringEngineering
10
Article|48 citations·2008
Nano-Electro-Mechanical Nonvolatile Memory (NEMory) Cell Design and Scaling
Woo Young Choi, T. Osabe, Tsu‐Jae King Liu
SJR Q2IEEE Transactions on Electron Devices

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The design and scalability of a nano-electro-mechanical memory (NEMory) cell are investigated via analytical modeling and finite element analysis (FEA) simulation. Proportionate scaling of all the cell dimensions provides for improved storage density together with low operating voltages and fast program/erase times. From FEA simulation, a 75-nm-long aluminum cantilever-beam NEMory cell is expected to

Electrical and Electronic EngineeringEngineering
11
Article|47 citations·2013
Dual-dielectric-constant spacer hetero-gate-dielectric tunneling field-effect transistors
Gibong Lee, Jung-Shik Jang, Woo Young Choi
SJR Q2Semiconductor Science and Technology

Hetero-gate-dielectric tunneling field-effect transistors (HG TFETs) with dual-dielectric-constant (k) spacers have been fabricated and characterized. They have a heterogeneous gate dielectric layer which consists of high-k material (HfO2) and SiO2 at the source and drain side, respectively. The dual-k spacer has an inner high-k and outer SiO2 spacer. The fabricated dual-k-spacer HG TFETs show higher on/off current ratio, on-current and better subthreshold slope than control TFETs which use only

Electrical and Electronic EngineeringEngineering
12
Article|36 citations·2024
Memristive Architectures Exploiting Self-Compliance Multilevel Implementation on 1 kb Crossbar Arrays for Online and Offline Learning Neuromorphic Applications
Sungjoon Kim, Sungjoon Kim, Hyeonseung Ji, Kyungchul Park, Hyojin So, Hyungjin Kim, Sungjun Kim, Sungjun Kim, Woo Young Choi
SJR Q1ACS Nano

This paper suggests the practical implications of utilizing a high-density crossbar array with self-compliance (SC) at the conductive filament (CF) formation stage. By limiting the excessive growth of CF, SC functions enable the operation of a crossbar array without access transistors. An AlO x /TiO y, internal overshoot limitation structure, allows the SC to have resistive random-access memory. In addition, an overshoot-limited memristor crossbar array makes it possible to implement vector-matr

Electrical and Electronic EngineeringEngineering
13
Article|35 citations·2015
Three-Dimensional Integration of Complementary Metal-Oxide-Semiconductor-Nanoelectromechanical Hybrid Reconfigurable Circuits
Woo Young Choi, Yong Jun Kim
SJR Q1IEEE Electron Device Letters

Complementary-metal-oxide-semiconductor(CMOS) and nanoelectromechanical (NEM) hybrid reconfigurable circuits are implemented for the first time using three-dimensional (3D) integration process. In addition, their operation is confirmed experimentally. For the fabrication of the 3D CMOS-NEM hybrid reconfigurable circuits, only the standard CMOS baseline process has been used except for the hydrofluoric acid vapor etch to release the NEM structures and focused-ion-beam patterning to define small p

Electrical and Electronic EngineeringEngineering
14
Article|34 citations·2010
Comparative Study of Tunneling Field-Effect Transistors and Metal–Oxide–Semiconductor Field-Effect Transistors
Woo Young Choi
SJR Q3Japanese Journal of Applied PhysicsOA

Electrical characteristics of tunneling field-effect transistors (FETs) have been compared with those of metal–oxide–semiconductor FETs (MOSFETs) in terms of subthreshold swing (SS), on/off current ratio, off current and on current. According to simulation results, tunneling FETs have advantages over MOSFETs for low-power consumption: smaller SS below 60 mV/dec at room temperature, lower off current, higher on/off current ratio and better immunity to short channel effects. However, low on curren

Electrical and Electronic EngineeringEngineering
15
Article|23 citations·2016
Influence of Intercell Trapped Charge on Vertical NAND Flash Memory
Woo Young Choi, Hyug Su Kwon, Yong Jun Kim, Byungin Lee, Hyunseung Yoo, Sangmoo Choi, Gyu-Seog Cho, Sung-Kye Park
SJR Q1IEEE Electron Device Letters

The influence of intercell trapped charge (ITC)—the charge trapped at the inter-cell nitride regions by fringe electric fields during program and erase operations—on vertical NAND (VNAND) flash memory is investigated. In addition to conventional degradation mechanisms such as tunnel oxide damage, ITC deteriorates the transconductance and read current of VNAND flash memory cells. The influence of ITC-induced degradation on VNAND flash memory is discussed, using both simulation and experimental re

Electrical and Electronic EngineeringEngineering

Research Areas

Electrical and Electronic EngineeringAtomic and Molecular Physics, and OpticsBiomedical EngineeringComputer Networks and CommunicationsArtificial IntelligenceMaterials Chemistry

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