J. T. Lee

Purpose Complications of implant prostheses have direct correlation with the increased use of implants for dental rehabilitation. In this study, we present cases of peri-implant oral malignancies (PIOM) around dental implants and a retrospective analysis of patients treated for PIOM. Methods The retrospective analysis was performed with patients t...

A multi-input processing spiking neural network inference system (MSS) is proposed to enhance the parallel processing capabilities of the spiking neural network (SNN) inference relative to the conventional SNN inference. Processing multiple input samples using MSS with shared synaptic arrays for compute-in-memory drastically reduces the number of s...

An electrochemical nanopattern formation (ENF) surface treatment was developed to overcome the limitations of conventional surface treatments. This study aimed to evaluate the cytocompatibility and preclinical efficacy of the newly developed ENF surfaces in comparison to conventional surfaces. The cytocompatibility of human mesenchymal stem cells,...

Conventional bioinert bone grafts often have led to failure in osseointegration due to low bioactivity, thus much effort has been made up to date to find alternatives. Recently, MXene nanoparticles (NPs) have shown prominent results as a rising material by possessing an osteogenic potential to facilitate the bioactivity of bone grafts or scaffolds,...

In this paper, we propose a novel neuron circuit with capacitive trans-impedance amplifier (CTIA) integrator to enhance the linearity of pre-synaptic current summation. The proposed neuron circuit achieved an improvement compared to the conventional neuron circuit with a current mirror, thereby maintaining the input node of a neuron circuit at virt...

Ammonia is a promising carbon-free hydrogen carrier. Owing to their nickel-rich anodes and high operating temperatures, solid oxide fuel cells (SOFCs) can directly utilize NH3 fuel—direct-ammonia SOFCs (DA-SOFCs). Lowering the operating temperature can diversify application areas of DA-SOFCs. We tested direct-ammonia operation using two types of th...

We propose a hybrid self-curing method based on the parasitic bipolar junction transistor (PBJT) inherent to metal-oxide-semiconductor field-effect transistor (MOSFET). The PBJT utilizes the positive feedback of impact ionization to flow a large current close to the channel, generating Joule heat. Unlike conventional self-curing methods, the PBJT-b...

Background Oral squamous cell carcinoma causes a significant proportion of global cancer morbidity and mortality. The aim of this study is to investigate whether the exhaled breath test can be a new, non-invasive, and effective method for diagnosing oral squamous cell carcinoma. Methods A comparative analysis of exhaled breath between patients wit...

In this paper, we analyze the impact of the leakage current of an AND-type synapse array on a spiking neural network (SNN). In order to evaluate the firing rate modulation affected by the leakage current of a synapse array, the electrical characteristics of a fabricated dual-gate synapse are measured and modeled. A SPICE circuit simulation shows a...

Oral cancer is a rare cancer that occurs in the oral cavity, in areas such as the tongue, roof of mouth, floor of mouth, gum, and inside cheek. Oral cancer has frequent local recurrence and lymph node metastasis even after curative surgery with radiation to prevent recurrence. However, more than 50% of patients show a relapse pattern, and it is dif...

We investigate the effects of length (L) and width (W) scaling on the low-frequency noise characteristics of the ferroelectric tunnel junction (FTJ). The FTJ is composed of metal/ferroelectric/dielectric/semicondu- ctor (TiN/HfZrO2/SiO2/n+ Si). In the high-resistance state, 1/f noise increases proportionally to 1/Wα Lβ (α ≅ 1, β > 1), whereas the s...

Recently, various memory devices have been actively studied as suitable candidates for synaptic devices, which are important memory and computing units in neuromorphic systems. One of the ways to manage these devices is off-chip training, where it is essential to transfer the pretrained weights accurately. Previous studies, however, have a few limi...

The design of the FET-type gas sensor affects various sensor performance factors such as sensitivity, noise, and power consumption. However, few studies comprehensively consider the impact of sensor design on the factors. Here, we show how the design of FET-type gas sensors influences a variety of performance factors and provide design guidelines f...

Objectives To investigate whether absence of maxillary lateral incisor (MXLI) would affect the status of maxillary canine (MXC) before and after secondary alveolar bone grafting (SABG) in patients with unilateral cleft lip and alveolus (UCLA) and unilateral cleft lip and palate (UCLP). Materials and Methods 47 male patients with UCLA and UCLP, who...

Purpose: This study aimed to evaluate the clinical usefulness of magnetic resonance (MR) neurography using the 3-dimensional double-echo steady-state with water excitation (3D-DESS-WE) sequence for the preoperative delineation of the facial and lingual nerves. Materials and methods: Patients underwent MR neurography for a tumor in the parotid gl...

Objectives Early detection of oral cancer is critical because the survival rate is reported to be 90%, whereas 45.5% for advanced oral cancer occur with neck metastasis. This study assessed the detection potential of oral tongue cancer and precancerous lesions using a convolutional neural network (CNN) and evaluated the effectiveness of EfficientNe...

In this article, for the first time, we proposed the side-shielded forksheet (S-FS) device to sustain extreme device scaling and to expand device design margins. Through the process simulations calibrated based on transmission electron microscopy (TEM) dimensions of the process integration modules, it is verified that n/p-type nanosheet (NS)-shaped...

We investigate the effects of postdeposition annealing (PDA) ambience on the nitrogen dioxide (NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) gas sensing performance in the Si-based field-effect transistor (FET)-type gas sensor having an indium–gallium–zinc oxide (IGZO) as a sensing mater...

The design of composite cathode microstructures is important for improving the performance of all-solid-state batteries (ASSBs). The microstructural properties can provide efficient ionic/electronic percolation, good cathode/solid electrolyte (SE) contact, and minimal void spaces. Although the effects of the size of cathode and SE particles have be...

A novel synaptic architecture based on a NAND flash memory structure is proposed as a high-density synapse capable of exclusive NOR (XNOR) operation for binary neural networks (BNNs). For the first time, a 4T2S-based synaptic architecture with a complementary input voltage that implements an equivalent bitwise XNOR operation is proposed. Two adjace...

The focus of gas sensor research has been on improving the response of individual sensors. However, in order to integrate sensors with CMOS circuits, a sensing system composed of an amplifier circuit with a voltage output is required. As such, in this work, we propose a novel gas sensing amplifier circuit composed of resistor- and FET-type gas sens...

Gaseous pollutants, including nitrogen oxides, pose a severe threat to ecosystems and human health; therefore, developing reliable gas-sensing systems to detect them is becoming increasingly important. Among the various options, metal-oxide-based gas sensors have attracted attention due to their capability for real-time monitoring and large respons...

In this work, we implement hardware-based spiking neural network (SNN) using the thin-film transistor (TFT)-type flash synaptic devices. A hardware-based SNN architecture with synapse arrays and integrate-and-fire (I&F) neuron circuits is presented for executing reinforcement learning (RL). Two problems were used to evaluate the applicability of th...

In this work, we present a hardware neural network with capacitor-based synaptic devices. A capacitor-based synaptic device was developed using a MOS capacitor structure with a charge trapping layer. Due to the flat band voltage shift by charge trapping and its non-linear ${C} - {V}$ characteristics, multilevel weight values could be implemented...

Most studies on gas sensors are focusing on improving the response of the sensor. However, noise characteristics should also be considered for the design of gas sensors with optimal performance. This paper investigates the effects of electrode structure on H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xli...

Through a comparative analysis of gate-all-around field-effect transistors (GAAFETs) with the same layout footprint as FinFETs of 3-nm technology nodes, the effect of the tapered fin shape on device performance is determined using the 3-D technology computer-aided design (TCAD) simulation. Moreover, this comparative study presents the most optimal...

Background The implants of pure titanium (Ti) and its alloys can lead to implant failure because of their poor interaction with bone-associated cells during bone regeneration. Surface modification over implants has achieved successful implants for enhanced osseointegration. Herein, we report a robust strategy to implement bioactive surface modifica...

We investigate the channel length ( ${L}$ ) scaling effects on the signal-to-noise ratio (SNR) of the field-effect-transistor (FET)-type gas sensor with a horizontal floating-gate. A sensing layer, 15 nm of indium-gallium-zinc-oxide thin film, is deposited by the radio frequency sputtering method. Nitrogen dioxide is used as a target gas. The low-...

In this article, the interface trap-assisted ferroelectric polarization in ferroelectric-gate field effect transistors (FeFETs) is investigated based on technology computer-aided design (TCAD) simulations. The metal–ferroelectric–metal (MFM) capacitors and FeFETs are fabricated to reflect ferroelectric and device model parameters to the simulations...

Anode-free all-solid-state batteries (AFASSBs), composed of a fully lithiated cathode and a bare current collector (CC) that eliminates excess lithium, can maximize the energy density (because of a compact cell configuration) and improve the safety of solid-state systems. Although significant progress has been made by modifying CCs in liquid-based...

Gas sensors with micro-heaters are being widely studied in various fields. However, there are few systematic studies examining the effect of embedded heaters on their reliability and gas detection features. In this work, we investigate the change in electrical characteristics of the heater that occurs when thermal stress and current stress are appl...

Selection of potential disease-specific biomarkers from saliva or epithelial tissues through next generation sequencing (NGS)-based protein studies has recently become possible. The early diagnosis of oral squamous cell carcinoma (OSCC) has been difficult, if not impossible, until now due to the lack of an effective OSCC biomarker and efficient mol...

Emerging solid-state lithium batteries demand a stable solid electrolyte against both Li anodes and high-voltage cathodes. The NASICON-type Li1.5Al0.5Ge1.5(PO4)3 (LAGP) solid electrolyte is highly tolerant to high-voltage operation and air environments, but it suffers from poor interfacial compatibility with Li anodes. Herein, we revisit the Li/LiP...

Ferroelectricity in hafnium oxide (HfOx) and its various applications have been rigorously investigated in recent years. In particular, most studies have focused on a non-centrosymmetric ferroelectric phase that is developed via the injection of external ions into HfOx. However, the drawbacks of doped HfOx, such as serious dopant variation and ther...

In this letter, we propose the variation-tolerant capacitive binarized neural network using the capacitance of 2-terminal MANOS memory devices. The capacitance-voltage characteristic of the synaptic device is shifted by program or erase operation. Two saturated regions of the C-V curve are used for representing the weight of the binarized neural...

Sensing performances of the Si-based field-effect transistor (FET)-type gas sensor are not only affected by sensing material characteristics but also by electrical properties of a transducer. Therefore, the optimization of transducer properties, including subthreshold swing, transconductance, and low-frequency noise (LFN) characteristics, is necess...

Background: The implants of pure titanium (Ti) and its alloys can lead to implant failure because of their poor interaction with bone-associated cells during bone regeneration. Surface modification over implants has achieved successful implants for enhanced osseointegration. Methods: Herein, we prepared sandblasted, large-grit, and acid-etched (SLA...

It has been reported that the HfOx-based metal–ferroelectric–insulator–semiconductor (MFIS) stack is one of the most feasible structures for memory applications in ferroelectric devices. In addition, in MFIS stacks, the formation of a high-quality thin insulator is considered to be a crucial process, because it determines the device performance and...

Hardware-based Spiking Neural Networks (SNNs) are regarded as promising candidates for the cognitive computing system due to its low power consumption and highly parallel operation. In this paper, we train the SNN in which the firing time carries information using temporal backpropagation. The temporally encoded SNN with 512 hidden neurons achieved...

Artificial Neural Networks (ANNs) have shown remarkable performance in various fields. However, ANN relies on the von-Neumann architecture, which consumes a lot of power. Hardware-based spiking neural networks (SNNs) inspired by a human brain have become an alternative with significantly low power consumption. In this paper, we propose on-chip trai...

Triple ionic-electronic conducting oxides, in which electron holes, oxygen ions, and protons are simultaneously mobile, are garnering massive attention as potential oxygen electrodes in protonic ceramic cells. While their high...

A gated diode with a charge trap insulator stack (Al₂O₃/Si₃N₄/SiO₂) is proposed as a synaptic device and its potentiation and depression operations have been demonstrated. Using the band-to-band tunneling current, the gated diode operates with low current (in nanoampere range) and is suitable for low-power hardware-based neural networks. Since the...

A bilateral gate-controlled S/D symmetric and interchangeable bidirectional tunnel field effect transistor (B-TFET) is proposed in this paper, which shows the advantage of bidirectional switching characteristics and compatibility with CMOS integrated circuits compared to the conventional asymmetrical TFET. The effects of the structural parameters,...

In this paper, electrically insulating branched polyethylenimine (PEI) is applied to a field effect transistor (FET) sensor platform for low relative humidity (RH) detection (< 20%) at room temperature. The platform contains horizontally aligned control gate and floating gate, so that PEI is readily formed by simple ink-jet printing process. The el...

The ferroelectric-metal field-effect transistor with recessed channel (RC-FeMFET) is proposed for one transistor dynamic random-access memory (1T-DRAM). Through technology computer-aided design (TCAD) simulations, the effects of inter-metal insertion on the FeFET with recessed channel (RCFeFET) is identified. By evaluating electric field (e-field)...

In this work, the low-frequency noise (LFN) characteristics of hafnium-zirconium oxide (HZO) ferroelectric field-effect transistors (FeFETs) with and without high-pressure forming gas annealing (HPA) treatment are investigated. The origin of $1/ {f}$ noise in the FeFET without HPA is changed from carrier number fluctuation to Hooge’s mobility flu...

Nowadays, The coming acceleration of global population ageing. When people get older, the importance of implants is emphasized. Dental implants have a crucial effect on life satisfaction. Many techniques have already been developed it. However, those still required many procedures. Shin et al suggested the new model based on MA. The electrochemical...

An oxide fin-based AND flash memory synaptic device is proposed and fabricated using a spacer patterning technology for a hardware-based binary neural network (BNN). A fin-like curved channel structure provides local electric field enhancement, which improves programming efficiency compared to planar-type flash synaptic devices. The fin-based AND f...

Sodium hydroxide or caustic soda is a corrosive agent that can cause extensive damage to the oral mucosa, lips, and tongue when ingested either accidentally or intentionally. These injuries include microstomia, shallow vestibule, ankyloglossia, speech impairment, loss of teeth and impairment in facial expression. In the present article, we report a...

A novel design method using unsigned input is proposed for a high-density and parallel synaptic string architecture capable of bit-wise operation and bit-counting utilizing NAND flash memory. Though the NAND flash memory has a cell string structure, unsigned binary input enables analogue and parallel bit-counting in NAND flash memory, while achievi...

We investigated the reversible phase evolution reaction of Li3InCl6 as a representative halide Li-ion conductor due to the reaction of H2O based on the density functional theory. To understand the surface reactivity of Li3InCl6, the hydrolysis reaction was calculated using the thermodynamically stable Li3InCl6 surface. We found that the low adsorpt...

Our aim was to investigate the bone regeneration capacity of powder-type biphasic ceramic scaffold (BCP powder), block-type BCP (BCP block), and collagen-added block-type BCP (BCP collagen) with different concentrations of recombinant human bone morphogenetic protein 2 (rhBMP-2) in an animal model. Four rabbits were assigned to each of the followin...

A novel floating fin-structured nanosheet (FNS) is proposed to improve the work function (WF) variation by the fluctuation of the space between channels ( ${T}_{{\text {sp}}}$ ) in vertically stacked nanosheet devices. Through computer aided design (TCAD) simulations with calibrated models, it is found that the WF variation induces the serious var...

In this letter, we propose a double-gated ferroelectric-gate field-effect-transistor (DG-FeFET) for processing-in-memory (PIM) operations in a single device for the first time. The proposed device is highly compatible with a conventional fin field-effect-transistor (FinFET) process and thus the scalable Fin FeFET with the completely sympatric doubl...

Objective: To investigate the phenotypes and predominant skeletodental pattern in pre-adolescent patients with Pierre-Robin sequence (PRS). Methods: The samples consisted of 26 Korean pre-adolescent PRS patients (11 boys and 15 girls; mean age at the investigation, 9.20 years) treated at the Department of Orthodontics, Seoul National University...

Ferroelectric tunnel junction (FTJ) has been considered as a promising candidate for next-generation memory devices due to its non-destructive and low power operations. In this letter, we demonstrate the guideline of interlayer (IL) engineering in the FTJs with metal-pure HfOx ferroelectric layer (FE)-insulator-semiconductor stacks to boost the dev...

In this work, a synaptic device for neuromorphic system is proposed and designed to emulate the biological behaviors in the novel device structure of core-shell dual-gate (CSDG) nanowire flash memory. Floating-body effect in the device and charge trapping/de-trapping in the nitride layer are found to be effective for short-term potentiation (STP),...

As the computing paradigm has been shifted toward edge computing, the security problem of edge devices has been attracting much attention. However, since edge devices have limited resources in terms of power and area, it is difficult to apply a conventional cryptography system. On the other hand, as a simple security application, a physical unclona...

In this study, the influence of CuO and ZnO sintering activators on the densification behavior, distribution of sintering activators, and electrical properties of Y-doped BaZrO3−δ proton conducting oxide were examined over a wide range of oxygen and water vapor partial pressures. With the use of 1 mol% CuO and 4 mol% ZnO, a relative density above 9...

In this article, hardware-based spiking neural networks (SNNs) using capacitor-less positive feedback (PF) neuron devices are designed. It was reported that the PF device can simultaneously process the excitatory and inhibitory signals. The PF device shows very steep subthreshold slope (SS < 1 mV/dec) due to the PF opertaion, leading to low-power a...

Positive-feedback (PF) device and its operation scheme to implement pulse width modulation (PWM) function was proposed and demonstrated, and the device operation mechanism for implementing PWM function was analyzed. By adjusting the amount of the charge stored in the n- floating body (Qn), the potential of the floating body linearly changes with ti...

Reinforcement learning (RL) using deep Q-networks (DQNs) has shown performance beyond the human level in a number of complex problems. In addition, many studies have focused on bio-inspired hardware-based spiking neural networks (SNNs) given the capabilities of these technologies to realize both parallel operation and low power consumption. Here, w...

Neuromorphic Systems In article number 2100064, Jong‐Ho Lee and co‐workers present a novel method to train neuromorphic systems in an on‐chip manner. The new method has the potential to be applied to various neuromorphic systems by reducing the circuit burden and design complexity of the conventional methods. The cover image shows the concept of a...

Nowadays, medical facilities are developing their treatment environment to provide better services to their patients. In particular, dental hospitals have been considered uncomfortable and uninviting spaces, which needs to change so that people can visit easily and feel more relaxed. However, only a few systematic studies have reported on the deman...

In this brief, we demonstrate the gate-first HfZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (HZO) fully depleted silicon-on-insulator (FDSOI) negative capacitance field-effect transistor (NCFET) with self-aligned nickel-silicide (NiSi) source and drain (S/D). Although the gate-first proc...

On‐chip training of neural networks (NNs) is regarded as a promising training method for neuromorphic systems with analog synaptic devices. Herein, a novel on‐chip training method called direct gradient calculation (DGC) is proposed to substitute conventional backpropagation (BP). In this method, the gradients of a cost function with respect to the...

A new artificial olfactory system based on a spiking neural network (SNN) and field-effect transistor (FET)-type gas sensors is proposed for quickly and reliably detecting toxic gases. A FET-type gas sensor was fabricated with a micro-heater, and an In2O3 film was used as a sensing material for detecting NO2 and H2S gases. The sensor was investigat...

Purpose: This study evaluated the long-term survival and success rates of dental implants placed with autogenous onlay block bone grafts harvested from the mandibular ramus. Materials and methods: Patients treated with onlay bone graft from the mandibular ramus due to a severe vertical alveolar defect from 2001 to 2017 were included in this stud...

Advanced 3-D synaptic devices with a stackable and-type rounded dual channel (RDC) flash memory structure are proposed for neuromorphic networks. and synaptic arrays composed of RDC flash devices enable program/erase (PGM/ERS) using Fowler-Nordheim (FN) tunneling, high-speed operation because of parallel read operations, and high density with multi...

The purpose of this study was to investigate three-dimensional facial soft tissue changes after bimaxillary orthognathic surgery (BOGS) in patients with cleft lip and palate. The samples consisted of 34 Korean young adult patients with skeletal class III malocclusion who underwent BOGS for maxillary advancement/posterior impaction and mandibular se...

Retention characteristics of 3D NAND Flash cells are investigated at various temperatures ( ${T}$ ) depending on the degree of program and erase. The $\Delta {V}_{\text {th}}$ for each condition is compared to understand the degradation of the retention characteristics attributable to vertical loss and/or lateral diffusion. In addition, the rela...

We have faced the challenges from atmosphere environment due to the exposing toxic gases or liquids. Moreover, we also need to test some gases such as acetone, ethanol, and petroleum for our health or safety. Therefore, it is important to develop various gas sensors for testing them. Sensing materials play important roles in determining the perform...