Sanghun Jeon

We report on 4.5-nm-thick Hf0.5Zr0.5O2 (HZO) thin-film-based ferroelectric tunnel junctions (FTJs) with a tungsten (W) bottom electrode. The HZO on the W electrode exhibits stable ferroelectricity with a remanent polarization of 14 μC/cm2, an enhanced tunneling electroresistance of 16, and excellent synaptic properties. We found that a large tensile stress was induced on a HZO thin film, owing to a low thermal expansion coefficient of the W bottom electrode. The low thermal expansion coefficient

The hygroscopic nature of lanthanide oxides such as Pr2O3, Sm2O3, Gd2O3, and Dy2O3 was characterized by means of x-ray photoelectron spectroscopy and its effect on the electrical characteristics of the compounds was investigated. Among the four samples, Pr2O3 was found to be the most reactive with water which can be attributed to the relatively large ionic radius and lower electronegativity of Pr. In contrast, Dy2O3 was the least reactive with water. A direct correlation between the hygroscopici

Electronic skin (e-skin) is designed to mimic the comprehensive nature of human skin. Various advances in e-skin continue to drive the development of the multimodal tactile sensor technology on flexible and stretchable platforms. e-skin incorporates pressure, temperature, texture, photographic imaging, and other sensors as well as data acquisition and signal processing units formed on a soft substrate for humanoid robots, wearable devices, and health monitoring electronics that are the most crit

The electrical characteristics of ZrOxNy prepared by NH3 annealing of ZrO2 were investigated for use in metal–oxide–semiconductor gate dielectric applications. Compared with conventional ZrO2, ZrOxNy exhibits excellent electrical characteristics such as high accumulation capacitance, low leakage current density, and superior thermal stability. Based on high resolution transmission electron microscope analysis of both ZrO2 and ZrOxNy samples which had been annealed at 800 °C for 5 min, the ZrO2 e

Paper-based electronic devices are attracting considerable attention, because the paper platform has unique attributes such as flexibility and eco-friendliness. Here we report on what is claimed to be the firstly fully integrated vertically-stacked nanocellulose-based tactile sensor, which is capable of simultaneously sensing temperature and pressure. The pressure and temperature sensors are operated using different principles and are stacked vertically, thereby minimizing the interference effec

A technique for invisible image capture using a photosensor array based on transparent conducting oxide semiconductor thin-film transistors and transparent interconnection technologies is presented. A transparent conducting layer is employed for the sensor electrodes as well as interconnection in the array, providing about 80% transmittance at visible-light wavelengths. The phototransistor is a Hf-In-Zn-O/In-Zn-O heterostructure yielding a high quantum-efficiency in the visible range.

The integration of electronically active oxide components onto silicon circuits represents an innovative approach to improving the functionality of novel devices. Like most semiconductor devices, complementary-metal-oxide-semiconductor image sensors (CISs) have physical limitations when progressively scaled down to extremely small dimensions. In this paper, we propose a novel hybrid CIS architecture that is based on the combination of nanometer-scale amorphous In-Ga-Zn-O (a-IGZO) thin-film trans

In the quest for highly scalable and three-dimensional (3D) stackable memory components, ferroelectric tunnel junction (FTJ) crossbar architectures are promising technologies for nonvolatile logic and neuromorphic computing. Most FTJs, however, require additional nonlinear devices to suppress sneak-path current, limiting large-scale arrays in practical applications. Moreover, the giant tunneling electroresistance (TER) remains challenging due to their inherent weak polarization. Here, we present

In this letter, we present a comparative study of the low-frequency noise behavior of single-layer InGaZnO and bilayer InZnO-InGaZnO thin-film transistors (TFTs). The normalized noise for the bilayer oxide TFT is three times lower than that for the single-layer oxide TFT, mainly due to the higher mobility of the thin interfacial InZnO layer. The carrier number fluctuation is the dominant low-frequency noise mechanism in both devices. The use of a high-mobility bilayer oxide TFT with scaled gate

Hafnia-based ferroelectric tunnel junctions (FTJs) have great potential for use in logic in nonvolatile memory because of their complementary metal-oxide-semiconductor process compatibility, low power consumption, high scalability, and nondestructive readout. However, typically, ferroelectrics have a depolarization field, resulting in poor endurance owing to the early dielectric breakdown. Herein, an outstandingly reliable and high-speed antiferroelectric HfZrO tunnel junction (AFTJ) is probed t

Hafnia-based ferroelectric memory devices with excellent ferroelectricity, low power consumption, and fast operation speed have attracted considerable interest with the ever-growing desire for nonvolatile memory in flexible electronics. However, hafnia films are required to perform a high temperature (>500 °C) annealing process for crystallization into the ferroelectric orthorhombic phase. It can hinder the integration of hafnia ferroelectric films on flexible substrates including plastic and po

The electrical and physical characteristics of PrTixOy, for use in metal-oxide-semiconductor gate dielectric applications were investigated. An amorphous layer of PrTixOy with an equivalent oxide thickness of 1 nm and a dielectric constant of 23 was formed by means of e-beam evaporation. Compared to Pr2O3, PrTixOy was found to exhibit excellent characteristics such as a high accumulation capacitance, a low leakage current density, a thin interfacial layer, and a lower reactivity to water. The su

Greatly improved ferroelectricity with an excellent remanent polarization of 20 μC/cm2 and enhanced tunneling electroresistance (TER) were achieved with TiN/HfZrO(HZO)/p-type Ge ferroelectric tunnel junctions (FTJs) annealed at a high pressure of 200 atmosphere (atm.). We found that the enhanced ferroelectric characteristics can be ascribed to the effective formation of an orthorhombic phase at high pressures. This was verified by the combined study of grazing angle incidence X-ray diffraction,