Band alignment of resistive random access memory (RRAM) switching material Ta2O5 and different metal electrode materials was examined using high-resolution X-ray photoelectron spectroscopy. Schottky hole barrier heights at the interface between were obtained, where electrodes consist with low to high work function (Φm,vac from 4.06 5.93 eV). Effective functions extracted study Fermi level pinning effect discuss dominant conduction mechanism. An accurate band is obtained can be used for RRAM...

In this letter, we report analog switching characteristics in an resistive random access memory device based on a TiW/Al2O3/Ta2O5/Ta stack. For device, both oxides were grown by using atomic layer deposition system and the oxygen vacancies found to exist at interface of these angle-resolved X-ray Photoelectron Spectroscopy. The exhibits behaviors. Multiple states achieved applying 128 consecutive identical pulses <20 μs duration stable for least 104 s. These show that is promising...

Significant improvements in the spatial and temporal uniformities of device switching parameters are successfully demonstrated <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm Ge}/{\rm TaO}_{x}$</tex></formula> bilayer-based resistive devices, as compared with non-Ge devices. In addition, reported devices also show significant reductions operation voltages. Influence Ge layer on -based random...

We present a novel selector made of doped-chalcogenide material. This not only achieves low holding voltage (0.2 V) and large on/off ratio (>10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> ), but also exhibits the high on-current density (>1.6 MA/cm xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) hysteresis window (1.2 V). Besides, excellent performances with ultra-low off-state leakage current (10 pA), switching speed (<10 ns),...

Ta2O5/TaOx heterostructure has become a leading oxide layer in memory cells and/or bidirectional selector for resistive random access (RRAM). Although atomic deposition (ALD) was found to be uniquely suitable depositing uniform and conformal films on complex topographies, it is hard use ALD grow suboxide TaOx layer. In this study, tantalum with composition of Ta2O5 were grown by ALD. Using Ar+ ion irradiation, the formed top observing Ta core level shift toward lower binding energy...

In this work, a non-idealities aware software-hardware co-design framework for deep neural network (DNN) implemented on memristive crossbar is presented. The device level non-ideal factors such as conductance variation, nonuniform quantization levels, device-to-device variation and programming failure probability are included in the model. At array level, impact of line resistance sneak path considered using new fast accurate estimation non-linearity offset peripheral circuits also...

A forming-free TaOx based RRAM cell is demonstrated with low operation voltage and large resistance window. devices Pt/TaOx/TiN Pt/TaOx/Ta film-stacks are investigated in this work. For TiN as top electrode (TE), the initial at OFF state, thus a forming process needed prior to subsequent switching operations. Ta TE, ON negating need for process. This attributed dielectric thinning effect caused by interfacial reaction between layers during gas anneal In addition, smaller |VSET| |VRESET|...

Electrode materials selection guidelines for oxide-based memory devices are constructed from the combined knowledge of observed device operation characteristics, ab-initio calculations, and nano-material characterization. It is demonstrated that changing top electrode material Ge to Cr Ta in Ta2O5-based resulted a reduction voltages current. Energy Dispersed X-ray (EDX) Spectrometer analysis clearly shows different scavenge oxygen ions Ta2O5 layer at various degrees, leading vacancy...

To understand the current conduction mechanism of TaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> RRAM with different top electrodes, we investigated field and temperature dependence charge transport. High resistance state shows a transition from Ohmic to Schottky emission then Poole-Frenkel as electric increases. Different electrode materials impact trap barrier heights which affect device performance.

Resistive switching behavior of TaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -based resistive devices is investigated at temperatures 25°C to 300°C. Both the set and reset voltages decrease with increasing temperature. Long retention (>10 years 150°C) good thermal stability were achieved for RRAM. At elevated from 240°C 300°C, low resistance state exhibits no significant change time. In contrast, high (HRS) shows degradation...

Of all the advantages exhibited by RRAM devices, e.g. low power consumption, fast switching speed, and especially good scalability are particularly striking for high density memory application. However, 3D still suffer from poor endurance during speed operation which limits its extensive applications. Here, we report transient control method enables a significant improvement of device stability endurance. We demonstrated stable under pulse in cells with different sizes 1 μm 200 nm. Endurance...

Ta/TaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -based Resistive Random Access Memory (RRAM) is studied using current-sweeping (I-sweep) DC switching operation. The self-compliance SET program achieved to prevent the device from current overshoot. and voltage are comparable with those measured by conventional voltage-sweeping (V-sweep) operation, but better uniformity realized. It found that high high-resistance-state (HRS)...

Implementation of analog RRAM technology for neuromorphic computing has faced unique challenges in terms endurance and variability as compared to the conventional digital memories. In this work, we demonstrate dual oxide layer devices with performance low working current, study trade-off switching speed, on/off ratio. We evaluate characteristics define correlation degradation behavior. Compromised specifications voltage, resistance range are suggested achieve integrative hardware...

Electrical pulse programming provides more practical and precise assessment of the resistive memory performance, also another angle view on switching mechanism investigation. This work presents bipolar TaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -based devices using electrical pulses. The SET process is almost independent width. However, significant reduction in RESET voltage current can be obtained long pulse, which attributed...

Al/Ta <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> /Pt RRAM cell was successfully demonstrated with stable bipolar switching. Band alignment for the structure of obtained using high-resolution X-ray photoelectron spectroscopy to investigate resistance switching behavior. Hole barrier heights Ta on metals Pt and Al were extracted core level valence band spectra. The energy alignments...

This paper presents the co-implementation of resistive random access memory inside a 180nm CMOS chip for low-cost, energy-efficient neuromorphic hardware accelerators. Systematic evaluation different TaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> -based ReRAM stacks was performed to derive optimal stack that shows high spatial and temporal uniformities without compromising back-end-of-line compatibility. Detailed comparison among...

In this paper, we investigated retention failure behavior in analog RRAM devices. The time was found to be longer TiW/ Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Ta xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> device than that of TiW/HfO device. Higher diffusion barrier for oxygen ions/vacancies causes a TiW/Al Multiple memory states were observed and stable at least 10...

A novel strained SiGe/TaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /Ta RRAM device is successfully demonstrated via a fully CMOS compatible process. The bottom electrode (BE) made of single crystalline SiGe layer where both n type and p as the BE. Typical bipolar switching behavior obtained for such devices. Cycle to cycle uniformity are investigated in this work, it found that BE shows better due dopant distribution Arsenic than...

We report a bipolar SiO2-based selector with threshold switching and self-compliance characteristics. The device turns ON under applied voltage of about +0.6 V, OFF when the drops below +0.04 V. Engineering copper (Cu) supply film is implemented by alloying Cu Ge2Sb2Te5 (GST). This enables appropriate modulation concentration migration in active SiO2 film, which responsible for reliable switching.

Ultra-thin (<; 5nm) RRAM stacks have been studied for read variability challenges and optimization guidelines advanced analog RRAM. Systematical AC testing studies in ultra-thin bilayer designs lead to important conclusions: (1) The barrier layer is essential maintain memory window low current fluctuation. (2) switching has thickness scaling limitation set by non-switching deep trap not a negligible fluctuation source. (3) work function selection of electrode metals can influence READ...