The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper we propose a novel oxide-based RRAM stack using hygroscopic oxide, doped Gd-O, as resistive switching layer integrated in a CMOS friendly flow. Operating at 50µA, the stack features large resistive window (>x100) and superior endurance lifetime (10^12) which is to our knowledge the record lifetime for CMOS compatible RRAM devices. Detailed benchmarking between conventional oxide-based...
We statistically investigated for the first time resistance stability in HfO2 RRAM devices in the short (μs to s) transient after switching. We show that, the resistance value of both logic states is not stable after programming and subject to large discrete stochastic fluctuations. The frequency of fluctuation is found to be time-decaying thus hindering its detection in DC condition but considerably...
In this paper we review a dynamic device model for filamentary RRAM in HfO-based dielectrics. We summarize its transient modeling features and its statistical properties. The model explains with satisfactory quantitative resolution all main features of the RRAM switching, not just the voltage, time and temperature dependence, but also statistical fluctuations resulting from atomistic motion and their...
Stacked HfOx based vertical RRAM with interface engineering for 3D cross-point architecture is fabricated using a cost-effective fabrication process. The excellent performances such as low reset current, fast switching speed, high switching endurance and disturbance immunity, good retention and self-selectivity are demonstrated in the fabricated HfOx based vertical RRAM devices. The scaling limit...
We propose for the first time a systematic evaluation of the performance and underlying trade-off of the use of ternary Hf1−xAlxOy oxides for RRAM application. We show that intermixing HfO2 and Al2O3 deposition cycles in a standard ALD process not only prevents crystallization of active layer but also significantly improve intrinsic retention and disturb-immunity properties at the expense of a small...
In this work, we present a systematic electrical characterization of TiN\HfO2\Hf\TiN RRAM elements from the variability perspective. Variability of both programmed resistance values and switching triggering voltages has been evaluated on small scaled cells in a wide operating current range (2µA till 500µA's), for different oxide stacks, in DC and pulsed conditions. For the first time device-to-device...
We report on the performance and reliability of the Hf/HfO2 RRAM cell with Ultra-Thin Oxide (UTO-RRAM). We show that cells with an oxide thickness of 3nm have basic performance (including speed, switching voltages, and the on/off window) similar to that of the cells with reference oxide (5–10nm thickness), while their operation requires a forming step at a voltage of only about 1.5V for a 40nm size...
We review our recent work on modeling of low current filamentary switching in amorphous HfO2 RRAM. The conduction is controlled by the width of the constriction, determining the electron transmission. The set and reset processes are modeled as a dynamic flow between two oxygen vacancy reservoirs connected by a narrow constriction. Reset is described as a dynamic balance between an upward and downward...
We demonstrate sub-500nA switching and tunable set voltage by inserting thin Al2O3 layer in TiN\HfO2\Hf\TiN RRAM cell. Stack engineering clearly led to novel insights into the switching phenomenology: (i) O-scavenging is key in the forming process and stack-asymmetry management; (ii) dielectric-stack thinning allows lower forming current; (iii) ‘natural’ (asymmetry-induced) reset switching takes place...
Here for the first time we discuss RRAM cell performance and reliability through process improvement. Excellent post-cycling (106) retention and post-bake retention and endurance have been achieved for the optimized process conditions. The optimized RRAM cells show potential for manufacturability and scalability for high density memory application.
In this work, we present a detailed electrical characterization of TiN\HfO2\Hf\TiN RRAM elements, and show for the first time the intrinsic switching characteristics in the low current operation regime (100uA till few uA's) of small scaled cells (20nm) under DC and fast ramps (up to 1MV/s) condition, using a newly proposed 2R test structure. The main characteristic parameters of the SET and RESET...
Metal-oxide-semiconductor (MOS) capacitors incorporating atomic-layer-deposited (ALD) LaO/HfZrO stacked gate dielectrics were fabricated. The experimental results reveal that the equivalent oxide thickness (EOT) is 0.65 nm, and the gate leakage current density (Jg) is only 1.9 A/cm2. The main current conduction mechanisms are Schottky emission, Poole-Frankel emission, and Fowler-Nordheim tunneling...
Metal-oxide-semiconductor (MOS) capacitors with atomic-layer-deposition (ALD) HfLaO or HfZrLaO high-κ gate dielectrics have been fabricated, and the reliability of time-dependent-dielectric-breakdown (TDDB) characteristics have also been analyzed. HfZrLaO shows a better performance in comparison with HfLaO. Moreover, some important parameters for HfZrLaO and HfLaO gate dielectrics are compared in...
HfO2-based resistive RAM (RRAM) devices have received intensive research attention in the recent years. Most of the HfO2-based RRAM system demonstrates promising performance in bipolar mode. However, HfO2-based RRAM devices in unipolar mode so far, still suffers from low endurance (<;500 cycles), and non-integratable electrode materials such as Pt or Au. In this work, CMOS-compatible Ni-containing...
In this work, the effect of the anode electrode-HfO2 interface on unipolar switching for HfO2-based RRAM is systematically investigated. It is found that the switching behavior can be improved not only by changing the anode electrode material (TiN vs. Pt), but also by engineering the anodic interface with thin M or MOx capping layers between the electrode and the HfO2 film, such as Ti or TiO. The...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.