Kyung Min Kim

Kyung Min Kim
Korea Advanced Institute of Science and Technology | KAIST · Department of Materials Science and Engineering

Ph.D.

About

71
Publications
28,012
Reads
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7,073
Citations
Additional affiliations
January 2013 - November 2013
Samsung Electronics
Position
  • Engineer
January 2011 - January 2013
Samsung Advanced Institute of Technology
Position
  • Research Staff Member
September 2008 - December 2010
Seoul National University
Position
  • Post Doctor

Publications

Publications (71)
Article
Full-text available
Stateful logic enables highly energy‐efficient computation because the time and energy consumption for data transfer between the memory and the computing units, such as central processing unit and graphics processors, in the traditional computation system can significantly be saved. This is due to the combined functionalities of logic operation and...
Article
Full-text available
Stateful logic provides an attractive device‐level solution in achieving in‐memory computation, which can solve the critical problem of the von Neumann bottleneck − “memory wall” − in the current computer architecture. Recently, fully functional stateful logic operations and cascading are reported using a TiOx‐based dual‐bit memristor. In that work...
Article
Full-text available
By combining the functions of Boolean gates and non‐volatile memory, stateful logic may enable significant savings in time and energy for computational processes that can be performed directly in main memory and for data analyses in edge environments. A simple reduction to practice this concept is demonstrated by Borghetti et al. in 2010 via a mate...
Article
Full-text available
A nociceptor is a critical and special receptor of a sensory neuron that is able to detect noxious stimulus and provide a rapid warning to the central nervous system to start the motor response in the human body and humanoid robotics. It differs from other common sensory receptors with its key features and functions, including the "no adaptation" a...
Article
Full-text available
A Pt/NbOx/TiOy/NbOx/TiN stack integrated on a 30 nm contact hole structure shows a programming current as low as 10 nA and 1 pA for the set and reset switching, respectively, and a self-rectifying ratio as high as ~105, which are suitable characteristics for low power memristor applications. Also it shows a forming-free characteristic. A charge tra...
Article
Thermochemical and electronic trapping/detrapping mechanism-based resistance switching in TiO2 is one of the most extensively researched topics in the field of resistance-switching random access memory (ReRAM). In this study, the subtle correlation between the formation and rupture of the Magnéli-based conducting filament (CF), which is the mechani...
Article
In article number 1600090, D. S. Jeong et al. review memristors and their potential application in new, energy saving forms of computation, including stateful logic and neuromorphic computing. Memristors in a cross-bar array format (background image) create a two-terminal voltage- or charge-driven non-volatile memory and logic component, serving as...
Article
In this Review, memristors are examined from the frameworks of both von Neumann and neuromorphic computing architectures. For the former, a new logic computational process based on the material implication is discussed. It consists of several memristors which play roles of combined logic processor and memory, called stateful logic circuit. In this...
Article
Full-text available
The impact of a series resistor (RS) on the variability and endurance performance of memristor was studied in the TaOx memristive system. A dynamic voltage divider between the RS and memristor during both the set and the reset switching cycles can suppress the inherent irregularity of the voltage dropped on the memristor, resulting in a greatly red...
Article
Full-text available
An integrated memory cell with a mem-ristor and a tri-layer crested barrier selector, showing repeatable nonlinear current-voltage switching loops is presented. The fully atomic-layer-deposited TaN1+x /Ta2 O5 /TaN1+x crested barrier selector yields a large nonlinearity (>10(4) ), high endurance (>10(8) ), low variability and low temperature depende...
Article
Full-text available
Resistance switching (RS) devices with ultra-thin Ta 2 O 5 switching layer (0.5-2.0 nm) with a cell diameter of 28 nm were fabricated. The performance of the devices was tested by voltage-driven current - voltage (I-V) sweep and closed-loop pulse switching (CLPS) tests. A Ta layer was placed beneath the Ta 2 O 5 switching layer to act as an oxygen...
Article
Pt/Ta2 O5 /HfO2- x /Ti resistive switching memory with a new circuit design is presented as a feasible candidate to succeed multilevel-cell (MLC) NAND flash memory. This device has following characteristics: 3 bit MLC, electroforming-free, self-rectifying, much higher cell resistance than interconnection wire resistance, low voltage operation, low...
Article
Full-text available
Electroforming behaviours of Ta2O5 resistance switching memory cell with a diameter of 28 nm and different thickness (0.5–2.0 nm) of Ta2O5 layer have been examined. The devices showed a constant forming electric field of 0.54 V/nm regardless of Ta2O5 thickness. The electroforming with negative bias to top TiN electrode was ascribed to electric fiel...
Article
A memristor device is demonstrated that produces uniform and controllable resistance switching by placing fixed resistors in series and in parallel with a memristor. The experiments utilize a Pt/Ta2O5/Ta crosspoint device that yielded a coefficient of variation, or relative standard deviation, less than 0.005 for both low resistance (R ON) and high...
Article
To facilitate the development of memristive devices, it is essential to resolve the problem of non-uniformity in switching, which is caused by the random nature of the filamentary switching mechanism in many resistance switching memories based on transition metal oxide. In addition, device parameters such as low- and high-state resistance should be...
Article
Full-text available
The resetting behaviors of Pt/TiO2/Pt resistive switching (RS) cell in unipolar RS operations were studied in detail through an experiment and by modeling. The experiment showed that the apparently highly arbitrary resetting current-voltage (I-V) curves could be grouped into three types: normal, delayed, and abnormal behaviors. A dual conical condu...
Article
Full-text available
Unipolar resistance switching (RS) in TiO2 thin films originates from the repeated formation and rupture of the Magnéli phase conducting filaments through repeated nano-scale phase transitions. By applying the Johnson-Mehl-Avrami (JMA) type kinetic model to the careful analysis on the evolution of transient current in a pulse-switching, it was poss...
Article
The influence of Ni vacancies on the chemistry and electronic structure of NiO thin films was investigated using X-ray absorption spectroscopy and extended X-ray absorption fine structure analysis. Changes in the electronic structures upon partial oxidation are mainly addressed. It is strongly suggested that the hole carriers are mostly delocalized...
Article
Full-text available
Tantalum-oxide-based bi-layered resistance-change memories (RRAMs) have recently improved greatly with regard to their memory performances. The formation and rupture of conductive filaments is generally known to be the mechanism that underlies resistive switching. The nature of the filament has been studied intensively and several phenomenological...
Chapter
The age of fast-moving information and computer technology is driven by silicon CMOS technology. Even though there seems to be no fundamental limit to scaling current devices to below 10 nanometers, there has been a shift toward functional diversification. This chapter proposes a new model and architecture based on the movement of oxygen vacancies...
Article
Full-text available
The synthesis, structure, and electrical performances of titanium dioxide (TiO2 and also doped TiO2) thin films, a capacitor dielectric for dynamic random access memory (DRAM) and a resistance switching material in resistance switching RAM (ReRAM), are reviewed. The three-dimensionality of these structures and the extremely small feature sizes (<20...
Conference Paper
The nature of threshold switching (TS) in AsTeGeSiN-based selector devices is comprehensively investigated. The scaling of the AC response is limited up to 5 ns due to a finite intrinsic delay time. An analytical model allows the accurate prediction of the TS nature, which can be merged to a numerical circuit simulation for providing essential guid...
Conference Paper
Full-text available
A highly reliable RRAM with multi-level cell (MLC) characteristics were fabricated using a triple-layer structure (base layer/oxygen exchange layer/barrier layer) for the storage class memory applications. A reproducible multi-level switching behaviour was successfully observed, and simulated by the modulated Schottky barrier model. Morevoer, a new...
Article
Full-text available
A tri-stable memristive switching was demonstrated on a Pt/TiO₂/Pt device and its underlying mechanism was suggested through a series of electrical measurements. Tri-stable switching could be initiated from a device in unipolar reset status. The unipolar reset status was obtained by performing an electroforming step on a pristine cell which was the...
Article
Full-text available
We report a physical model for multilevel switching in oxide-based bipolar resistive memory (ReRAM). To confirm the validity of the model, we conduct experiments with tantalum-oxide-based ReRAM of which multi-resistance levels are obtained by reset voltage modifications. It is also noticeable that, in addition to multilevel switching capability, th...
Article
Resistance switching behaviors in a Pt/In2Ga2ZnO7 (IGZO)/TiO2/Pt sample were examined for their potential use in diode-free memory integration. The In-Ga-Zn-O (IGZO) layer worked as the semiconductor layer, exhibiting accumulation or depletion of carriers depending on the polarity of the bias. Electroforming was possible only under the IGZO depleti...
Article
Full-text available
Electronic bipolar resistive switching and its degradation in the Pt/TiO2/Pt structure were studied. The electronic bipolar switching was induced from the asymmetric trap distribution of the structure under its unipolar reset state. The imbalanced migration of oxygen accompanied by electronic switching significantly degrades switching endurance. In...
Article
A modified biasing scheme was adopted to improve the electrical endurance characteristics of conducting filamentary resistive switching (RS) in a Pt/TiO2/Pt RS cell. The modified bias scheme included the application of bias voltages with alternating polarity, even though RS proceeds in non-polar mode, which results in the stable distribution of eac...
Article
Full-text available
The detailed mechanism of electronic bipolar resistance switching (BRS) in the Pt/TiO(2)/Pt structure was examined. The conduction mechanism analysis showed that the trap-free and trap-mediated space-charge-limited conduction (SCLC) governs the low and high resistance state of BRS, respectively. The SCLC was confirmed by fitting the current-voltage...
Article
Full-text available
This review article summarized the recent understanding of resistance switching (RS) behavior in several binary oxide thin film systems. Among the various RS materials and mechanisms, TiO(2) and NiO thin films in unipolar thermo-chemical switching mode are primarily dealt with. To facilitate the discussions, the RS was divided into three parts; ele...
Article
Filamentary resistance switching (RS) is one of the more obvious and useful phenomena in the family of RS mechanisms. In filamentary RS, the long reset switching time and substantially large power consumption are the critical obstacles for microelectronic applications. In this study, an innovative solution to overcome this reset problem is suggeste...
Article
Full-text available
The bipolar resistive switching mechanisms of a p-type NiO film and n-type TiO2 film were examined using local probe-based measurements. Scanning probe-based current–voltage (I–V) sweeps and surface potential/current maps obtained after the application of dc bias suggested that resistive switching is caused mainly by the surface redox reactions inv...
Article
Full-text available
Ru top electrode etching techniques for Ru/TiO2/Ru (RTR) thin film capacitor fabrication were examined. A dry etching process using a plasma mixture of O-2, Cl-2, and Ar gases deteriorated the leakage current properties significantly, which were not recovered by postannealing processes. The surface roughness was not a critical factor in determining...
Article
Full-text available
Ru nano-dots were embedded in a Pt/TiO2/Pt resistive switching cell to improve the uniformity of the switching parameters. The TiO2 film grown on the Ru nano-dots had a rutile structure locally whereas other parts of the TiO2 film had an anatase structure. The rutile-structured TiO2 formed conducting filaments easily and their rupture was much more...
Article
Full-text available
The relations between the reset current I<sub>R</sub> , room temperature filament resistance R<sub>0</sub> , and third harmonic coefficient B<sub>0</sub> were evaluated by a conical filament model. It was found that I<sub>R</sub>∼1/R<sub>0</sub> when the filament is either very weak, where the filament is more conical, or quite strong, where the fi...
Article
A phase change memory cell was fabricated by stacking plasma-enhanced cyclic chemical-vapor-deposited Ge2Sb2Te5 (GST) and atomic layer deposited TiO2 thin films. Different pairs of resistance states were obtained by controlling the current flow, which can be used to achieve higher memory density by multilevel operation. The multiresistance states o...
Article
Kirchhoff's law was used to examine the electrical specifications of selection diodes, which are essential for suppressing the read interference problems in nano-scale resistive switching cross bar arrays with a high block density. The diode in the cross bar array with a 100 Mb block density should have a reverse/forward resistance ratio of > 10(8)...
Article
Full-text available
The switching mechanism of the bipolar resistive switching behavior on NiO films was examined using local probe based measurements. Unlike the unipolar switching normally observed on a metal-insulator-metal structure, repetitive bipolar switching was observed on NiO films when a local probe was used as the top electrode. Surface potential and curre...
Article
Full-text available
This study examined the effects of electrical forming methods on the bipolar resistance switching (BRS) behavior in Pt/TiO2/Pt sandwich structures. The BRS is confined to a region near the ruptured end of conducting nanofilaments, which are composed of a TinO2n − 1 Magnéli phase formed by electroforming. The intermediate phase with an oxygen vacanc...
Article
The localized electrical conduction behaviour of a resistive switching TiO2 film was examined by conductive atomic force microscopy (CAFM). Localized filamentary electrical conduction was well resolved with a negative tip bias with respect to the Pt bottom electrode whereas almost uniform electrical conduction was observed with a positive bias. The...
Article
Full-text available
This study examined the properties of Schottky-type diodes composed of Pt/TiO(2)/Ti, where the Pt/TiO(2) and TiO(2)/Ti junctions correspond to the blocking and ohmic contacts, respectively, as the selection device for a resistive switching cross-bar array. An extremely high forward-to-reverse current ratio of approximately 10(9) was achieved at 1 V...
Article
Full-text available
The electrical conduction mechanism within a resistive switching TiO <sub>2</sub> film in its bipolar high resistance state was examined by ac impedance spectroscopy and dc current-voltage measurements. Bipolar switching, which can be initiated from a unipolar high resistance state, was attributed to both modulation of the Schottky barrier height a...
Article
Full-text available
This study examined the parameter controlling the set-state resistance (Rset) of a Pt/TiO2/Pt resistive switching (RS) cell in unipolar RS mode. Although the compliance current in the current-voltage sweep had some effect on the Rset, the uncontrolled flow of charge from the parametric analyzer prevented making an accurate estimation of the paramet...
Article
Full-text available
Resistance switching in metal oxides could form the basis for next-generation non-volatile memory. It has been argued that the current in the high-conductivity state of several technologically relevant oxide materials flows through localized filaments, but these filaments have been characterized only indirectly, limiting our understanding of the sw...
Article
Full-text available
The parameters determining the set state current and reset voltage, determined by the strength of formed filaments, were examined using current pulse and voltage driven current-voltage (I-V) sweeps. In the pulse switching measurement, the total current flow, including overshooting noise effect at the moment of set switching, was found to determine...
Article
Full-text available
A technique for dry etching a rutile TiO2 film in a Ru/TiO2/Ru capacitor structure was evaluated considering the electrical performance of the dielectric film. Ar + Cl-2, CF4, and SF6 etching gases were used to dry etch the TiO2 film. The Ar + Cl-2 and CF4 gases largely degraded the leakage current behavior, which was not recovered by the curing an...
Article
Full-text available
The effects of the external load resistance on the resistive switching (RS) behavior of Pt/TiO(2)/Pt RS cells were examined using model calculations and experiments. With increasing load resistance, the reset voltage increased more rapidly than the set voltage, which eventually resulted in RS failure. For the experiment, various electrode materials...
Conference Paper
The resistance switching (RS) behaviors of TiO2 and TiO2/NiO thin films were examined. The presence of conductive nano-filaments was confirmed directly by high-resolution transmission electron microscopy (HRTEM) in a Pt/TiO2/Pt system. The HRTEM images identified Magnéli structured filaments (mostly Ti4O7 phase) of both set and reset states. The lo...
Article
Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009
Article
Full-text available
This study examined the relationship between the conducting filament resistance and reset voltage during the resistance switching of TiO2 thin films assuming a filament with a conical shape. There was a critical resistance ( ∼ 20 Ω) of the set state above and below which the filament responded differently in response to the current. Maintaining a h...
Article
Phase change memory cells were fabricated using plasma-enhanced cyclic chemical-vapor-deposited Ge2Sb2Te5 (GST) thin films deposited on 300 nm diameter TiNW contact plugs formed in a SiO 2 layer. A 2, 4, and 8 nm thick atomic deposited TiO2 layer was interposed between the GST and underlayer containing the contact plug. The necessary reset current...
Article
A Schottky-type diode switch consisting of a Pt /( In , Sn )<sub>2</sub> O <sub>3</sub>/ Ti O <sub>2</sub>/ Pt stack was fabricated for applications to cross-bar type resistive-switching memory arrays. The high (0.55 eV ) and low potential barrier at the Ti O <sub>2</sub>/ Pt and Ti O <sub>2</sub>/( In , Sn )<sub>2</sub> O <sub>3</sub> junctions, r...
Article
The selective growth of stochiometric Ge2Sb2Te 5 (GST) on the TiN plugging material in the contact hole that was formed in the SiO2 dielectric layer was studied by atomic layer desorption (ALD) and chemical vapor desorpion (CVD). A contact structure with a top open diameter of 300 nm having TiN/W plugging material in a 500 nm thick SiO2 layer was f...
Article
Full-text available
The filamentary resistance switching mechanism of a Pt/40 nm TiO2/Pt capacitor structure in voltage sweep mode was investigated. It was unambiguously found that the conducting filaments propagate from the cathode interface and that the resistance switching is induced by the rupture and recovery of the filaments in the localized region (3–10 nm thic...
Article
The resistance switching mechanism of TiO2 films under voltage sweep mode was investigated. From the observed soft set of Pt/TiO2/Pt sample and from the polarity-dependant switching behavior of Ir(O)/TiO2/Pt sample, local rupture and recovery of conducting filaments near the anode interface wer identified as the switching mechanism. This is consist...
Article
A capacitive probe array with a polycystalline--probe capacitor structure was fabricated. The small signal capacitance-voltage characteristics of the array were measured under various bias voltages applied to an Al electrode which was capacitively coupled with the probe by an interlayer dielectric. The capacitance of the probe changed with the Al e...