Memory maps : Reading RRAM devices without power consumption

´A comparative study of MIM-RRAM structures with different insulator materials is presented. Admittance memory mapping was carried out at 0 V dc bias, revealing two clearly separated states, both in terms of conductance and susceptance. The memory in the ON state can be modeled by means of a two parameter (resistance and inductance) equivalent circuit. The parameter extraction provides memory maps for the resistance and the inductance as well. The transition shapes between the ON an OFF state are different for each structure due to specific physical mechanisms. © The Electrochemical Society.Peer reviewe

Study of the influence of the dielectric composition of Al/Ti/ZrO2:Al2O3/TiN/Si/Al structures on the resistive switching behavior for memory applications

The memory behavior of Al/Ti/ZrO2:Al2O3/TiN/Si/Al devices is investigated in this work. They are adequate to be used as resistive switching memories, with two clearly different states. Besides, intermediate states are also accessible in a controllable manner. The electrical characterization in terms of admittance parameters provides relevant complementary information. The cation ratio influences the memory maps and can be changed to obtain specifically sized shape of the maps. © The Electrochemical Society.Peer reviewe

Admittance memory cycles of Ta2O5-ZrO2-based RRAM devices

The resistive switching behavior of Ta2O5-ZrO2-based metal-insulator-metal devices was studied. Asymmetrical and repetitive current-voltage loops were observed. Excellent control of admittance parameters in the intermediate states between the high and low resistance ones was achieved, demonstrating suitability to analog and neuromorphic applications. Admittance memory cycles provide relevant information about the switching mechanism, in which the existence of two different metallic species in the dielectric seems to play an important role.Peer reviewe

In situ characterization of atomic layer deposition processes by a mass spectrometer

In situ characterization of the chemical reactions in atomic layer deposition (ALD) processes in flow-type reactors is an important and challenging task. For this purpose, a quadrupole mass spectrometer has been integrated to an ALD reactor. The special features of this setup are described and its performance is demonstrated by studies on ALD oxide processes employing Al(CH3)3, Ti(OC2H5)4, Ta(OC2H5)5 and Nb(OC2H5)5 as metal precursors and water as the oxygen source

Analysis of the performance of Nb(2)O5-doped SiO2-based MIM devices for memory and neural computation applications

Since two decades ago, research on resistive memories has continuosly grown, gathering relevance through the variety of different technologies that fit into the non-volatile memories' area. In this study, we discuss the performance and electrical characteristics of RRAM cells constituted by MIM stacks with dielectric formed by Nb2O5-doped SiO2. We report experimental results that show a clear improvement in the resistive behavior of the devices and an excellent analogical control of the intermediate levels between high-resistance and low-resistance states.Peer reviewe

Optical and dielectrical characterization of atomic layer deposited Nb2O5 thin films

Nb2O5 films were grown by atomic layer deposition using (tert-butylimido)tris(diethylamido)niobium as the niobium source and ozone as the oxygen source. The effects of deposition and post-deposition annealing conditions, physical thickness as well as the phase composition on the dielectric properties of Nb2O5 thin films have been investigated. In addition, the optical properties of the films have been evaluated. It was found that by tuning the deposition parameters and post deposition treatments it was possible to obtain high k-values up to 120 with reasonably low leakage current

High-performance imido-amido precursor for the atomic layer deposition of Ta2O5

The atomic layer deposition of Ta2O5 thin films was studied using a novel imido–amido precursor tBuN = Ta(NEt2)3. This precursor is liquid at room temperature, possesses good volatility and is reactive toward both water and ozone as the oxygen sources. The deposition temperature was varied from 125 to 475 °C. Saturated film growth was confirmed at 325 °C for both water and ozone processes, and a region of constant growth rate was observed between 125 and 350 °C when using ozone as the oxygen source. All the films were amorphous in the as-deposited state and crystallized at around 700 °C into orthorhombic Ta2O5, regardless of the applied oxygen source. X-ray photoelectron spectroscopy demonstrated high purity of the films deposited at temperatures higher than 225 °C. Atomic force microscopy revealed that the films were smooth (rms <0.3 nm) and uniform. The films exhibited permittivity values of ~25 and low leakage current