Korea Advanced Institute of Science and Technology · Engineering
Professor Junghyeon Hwang's research lab specializes in advanced ferroelectric materials and devices, with a primary focus on hafnia-based ferroelectrics for next-generation nonvolatile memory and neuromorphic computing applications. The lab explores fundamental mechanisms of ferroelectricity in ultra-thin films, particularly fluorite-structured HfO₂ and ZrO₂, and develops innovative device architectures such as ferroelectric tunnel junctions (FTJs) and FeFETs to enhance performance, scalability, and reliability. Key research directions include interface engineering, high-pressure annealing techniques, and low-damage fabrication processes to improve polarization, reduce leakage currents, and mitigate degradation effects like wake-up and fatigue.
Figures are computed from collected data and may differ slightly.
The various structures of ferroelectric tunnel junctions (FTJs) are widely studied. Among them, metal-ferroelectric-semiconductor (MFS) FTJs show great tunneling electroresistance (TER) ratio by forming a depletion region. However, the poor ferroelectricity of hafnia on semiconductor electrodes degrades the TER ratio. This study employed high-pressure annealing with forming gas to improve the ferroelectric properties of MFS FTJs. We achieved a high 2Pr value (47.54 μc/cm <sup xmlns:mml="http://w
The interest in ferroelectric tunnel junctions (FTJ) has been revitalized by the discovery of ferroelectricity in fluorite-structured oxides such as HfO<sub>2</sub> and ZrO<sub>2</sub> . In terms of thickness scaling, CMOS compatibility, and 3D integration, these fluorite-structured FTJs provide a number of benefits over conventional perovskite-based FTJs. Here, recent developments involving all FTJ devices with fluorite structures are examined. The transport mechanism of fluorite-structured FTJ
Hafnia-based ferroelectric (FE) devices have attracted significant attention as nonvolatile memory devices due to their compatibility with complementary metal–oxide–semiconductor processes. Among them, the FE tunnel junction (FTJ) has been considered as the next-generation of nonvolatile memory devices owing to its neuromorphic characteristics and nondestructive read operation as well as the high-density integration. However, degradation of ferroelectricity in a thin hafnia film causes a reduced
We demonstrate that a non-volatile majority function logic is formed by a 1T-nC <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{storage}$ </tex-math></inline-formula> -1C <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{read}$ </tex-math></inline-formula> cell in which a hafnia ferroelectric capacitor is used for computin
Hafnia-based ferroelectric field-effect transistors (FeFETs) with low power, scalability, and nonvolatile switching can overcome the performance limitations of conventional von Neumann computing technology. However, achieving a large memory window and excellent endurance in FeFET devices composed of two capacitors, such as ferroelectric and interfacial insulator capacitors, remains a challenge due to the strong electric field applied to the insulator, which accounts for the low permittivity ( <i
This study presents a low-damage metallization process for ultra-thin hafnia-based ferroelectric films, achieving high polarization, low leakage currents, and reduced wake-up effect, paving the way for scalable and reliable FeRAM applications.
Metal-ferroelectric-metal-insulator-semiconductor (MFMIS) FeFETs have significant potential for use in non-volatile memory applications. This is primarily due to their compatibility with CMOS technology and reliable switching characteristics. Previous studies have primarily concentrated on the endurance and memory window properties, while this study focuses on the short-term (<<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math not
In this study, we present a remarkable improvement in the performance of hafnia-based ferroelectric tunnel junctions (FTJs) using oxygen scavenging technology and extremely low-damage (ELD) deposition, leading to a significant increase in the tunneling electroresistance ratio $({\mathrm {TER}}) (\gt 2 \times 10^{4})$, on-current density $(\gt 10^{-2}\mathrm{A} /cm^{2})$, and self-rectifying ratio $({\mathrm {RR}}) (\gt 1.5 \times 10^{3})$. First-principles DFT simulations were also used to evalu
An ultrathin InO interlayer supplies oxygen to HZO, curing the interface and thinning the dead layer, enabling more uniform ferroelectric switching with lower leakage and improved reliability.
Short O 2 RTA converts Mo into a MoO x -rich interface ( φ ≥ 5.5 eV), suppressing trap formation and stabilizing imprint in HZO. This in-situ route avoids sputtered MoO 3 and enables robust FTJ endurance.
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