Ying- Chen

Memcomputing (Memristor + Computing) in Intrinsic SiO x -Based Resistive Switching Memory: Arithmetic Operations for Logic Applications

In this paper, implication (IMP) operations are demonstrated in a circuit with two SiOx-based memristors and a CMOS transistor. Specifically, a circuit with two one-diode and one-resistor (1D1R) memory elements and a transistor are designed to perform the IMP operations. A circuit consisting of a

Dynamic conductance characteristics in HfOx-based resistive random access memory

4 \times 4

HfO 2 -based In 0.53 Ga 0.47 As MOSFETs (EOT≈10Å) using various interfacial dielectric layers

crossbar 1D1R memristor array together with selection transistors is proposed and used to realize the functionality of a one-bit, full adder in 43 steps. Compared with CMOS logic circuits, the advantages and disadvantages of memristor-enabled logic circuits are discussed. This result suggests that the memristor-enabled logic circuit is most suitable for low-power and high-density applications, as well as a simple and robust approach to realize programmable memcomputing chips compatible with large-scale CMOS manufacturing technology.

Unidirectional threshold resistive switching in Au/NiO/Nb:SrTiO3 devices

Characteristics of HfOx-based resistive switching memory (RRAM) in Al/HfOx/Al and Al/AlOx/HfOx/Al structures were studied using a dynamic conductance method. Step-like RESET behaviors as well as pre- and post-RESET regions of operation were characterized. The results indicated that defects at the oxide interface caused cycling issues in the Al/AlOx/HfOx/Al structure. No such RESET behavior was observed for the Al/HfOx/Al structure. Current induced over-heating, which caused an early RESET event, could be avoided using current-sweep technique that caused less electrical and thermal stress in localized regions. The experimental results not only provided insights into potential reliability issues and power management in HfOx-based RRAM, but also helped clarifying the resistive switching mechanisms.

Factors enhancing In 0.7 Ga 0.3 As MOSFETs and tunneling FETs device performance

This work compares device performance for In<inf>0.53</inf>Ga<inf>0.47</inf>As M OSFETs using single HfO<inf>2</inf> gate dielectric with stacked gate dielectrics using various interfacial layers between HfO<inf>2</inf> and In<inf>0.53</inf>Ga<inf>0.47</inf>As substrate including Al<inf>2</inf>O<inf>3</inf>, HfAlO<inf>x</inf>, LaAlO<inf>x</inf>, and LaHfO<inf>x</inf>. Of the gate stacks studied, Al<inf>2</inf>O<inf>3</inf>/HfO<inf>2</inf>, HfAlO<inf>x</inf>/HfO<inf>2</inf>, and LaAlO<inf>x</inf>/HfO<inf>2</inf> bilayer gate dielectrics exhibit lower subthreshold swing, higher drive current and transconductance compared to single HfO<inf>2</inf> with similar equivalent oxide thickness (EOT) of about 10Å. This is believed t o be due to better interface quality between interfacial dielectrics and substrate, and confirmed by frequency dispersion and interface state density measurements.

Scaling Effect on Silicon Nitride Memristor with Highly Doped Si Substrate

A voltage-induced unidirectional threshold resistive switching has been reported for Au/NiO/Nb:SrTiO3 devices fabricated by pulsed laser deposition. The devices show the threshold resistive switching behavior only for the positive voltages, determined by the forming process. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the as-grown samples with different thicknesses suggest that the I-V and C-V properties are dominated by the Schottky junction at the NiO/Nb:SrTiO3 interface and NiO film, respectively, indicating the formation of conductive filaments in NiO film. Furthermore, the effect of NiO-film thickness on the resistive switching, as well as the I-V and C-V characteristics, indicates that the unidirectional threshold resistive switching originates from the combined contributions of the interfacial Schottky junction modulation and the bipolar threshold switching related to the unstable conductive filament in NiO film. Our research results provide additional insights into t...

A universal model for interface-type threshold switching phenomena by comprehensive study of Vanadium oxide-based selector

We demonstrate key factors enabling mobility improvement at both low charge density and high density (>5×10¹²/cm²) in In<inf>0.7</inf>Ga<inf>0.3</inf>As quantum-well MOSFETs. We further show sub-threshold swing (SS) and on-current (I<inf>d</inf>) improvement in tunneling FETs (TFETs). By reducing EOT, optimizing the top-barrier/high-к interface, and confining carriers in In<inf>0.7</inf>Ga<inf>0.3</inf>As channel using In<inf>0.52</inf>Al<inf>0.48</inf>As bottom-barrier, SS and mobility of MOSFETs were improved from 152 to 99 mV/dec and from ∼2500 to ∼5000 cm²/V-s, respectively. TFETs achieved small SS (96 mV/dec) and high I<inf>d</inf> (55 µA/µm) due to low EOT and abrupt, vertical insitu grown III–V epitaxial junctions.

Comprehensive study of intrinsic unipolar SiOx-based ReRAM characteristics in AC frequency response and low voltage (< 2V) operation

A feasible approach is reported to reduce the switching current and increase the nonlinearity in a complementary metal-oxide-semiconductor (CMOS)-compatible Ti/SiNx /p+ -Si memristor by simply reducing the cell size down to sub-100 nm. Even though the switching voltages gradually increase with decreasing device size, the reset current is reduced because of the reduced current overshoot effect. The scaled devices (sub-100 nm) exhibit gradual reset switching driven by the electric field, whereas that of the large devices (≥1 µm) is driven by Joule heating. For the scaled cell (60 nm), the current levels are tunable by adjusting the reset stop voltage for multilevel cells. It is revealed that the nonlinearity in the low-resistance state is attributed to Fowler-Nordheim tunneling dominating in the high-voltage regime (≥1 V) for the scaled cells. The experimental findings demonstrate that the scaled metal-nitride-silicon memristor device paves the way to realize CMOS-compatible high-density crosspoint array applications.

Characteristics of Nb-doped SrTiO 3 and HfO 2 -based selector devices

For the first time, a comprehensive study of Vanadium oxide-based selector characteristics with a universal model observed by thermal and electrical induced threshold switching (TS) phenomena at interface is presented in this work. The model can explain that the resistance evolution by thermal temperature in TS behaviors, as well as the resistance gradually increases with cycling (“seasoning effect”). Compatible current density (107∼109 A/cm2) and selectivity (∼100) with physical understanding of evolution in energy barrier and MIT metallic state modulation are studied. The results show a promising design guideline for future storage-class memory (SCM) applications.

A synaptic device built in one diode–one resistor (1D–1R) architecture with intrinsic SiOx-based resistive switching memory

Intrinsic unipolar SiOx-based Resistive-RAM (ReRAM) characteristics have been investigated. The cross-bar MIM structures have been examined under AC frequency response, by varying device area, temperature and current states. The results provide additional insights into the hopping/switching mechanisms. For the first time, by using SiOx/HfOx stacking engineering, we have developed a low-voltage operation (<; 2V) for SiOx-based ReRAM. The SiOx/HfOx stacking optimization not only maintains the RS behaviors even in air environment without any programming window degradation, but also further reduces the switching voltage below 2V.