Patrice Gonon

Crosslinking of porous SiOCH films involving Si–O–C bonds: Impact of deposition and curing

This paper focuses on the properties of nanoporous SiOCH thin films deposited using a porogen approach by plasma enhanced chemical vapor deposition. The impact of deposition temperature, porogen loading and porogen removal treatment is investigated using Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance analysis, and electrical and mechanical measurements. This work shows that a higher deposition temperature allows limiting the film shrinkage during the porogen removal treatment and leads to the best compromise in term of electrical and mechanical properties. Beside, the effect of Si–O–C bonds on the enhancement of mechanical properties is promoted since a typical crosslinking mechanism is highlighted in case of ultraviolet curing.

Frequency Effect on Voltage Linearity of

This letter deals with the electrical and wideband frequency characterizations of metal-insulator-metal capacitors integrating medium-¿ material, ZrO2. In particular, this letter focuses on the frequency effect on the voltage linearity of these capacitors and material. The dependence of the voltage-capacitance coefficient (VCC) ¿ is, for the first time, studied from 1 kHz to 1 GHz. Intrinsic or extrinsic material origin of the VCC are discussed.

\hbox{ZrO}_{2}

Resistance switching is studied in HfO2 as a function of the anode metal (Au, Cu, and Ag) in view of its application to resistive memories (resistive random access memories, RRAM). Current-voltage (I-V) and current-time (I-t) characteristics are presented. For Au anodes, resistance transition is controlled by oxygen vacancies (oxygen-based resistive random access memory, OxRRAM). For Ag anodes, resistance switching is governed by cation injection (Conducting Bridge random access memory, CBRAM). Cu anodes lead to an intermediate case. I-t experiments are shown to be a valuable tool to distinguish between OxRRAM and CBRAM behaviors. A model is proposed to explain the high-to-low resistance transition in CBRAMs. The model is based on the theory of low-temperature oxidation of metals (Cabrera-Mott theory). Upon electron injection, oxygen vacancies and oxygen ions are generated in the oxide. Oxygen ions are drifted to the anode, and an interfacial oxide is formed at the HfO2/anode interface. If oxygen ion mobi...

-Based RF Metal–Insulator–Metal Capacitors

This paper presents a novel fully passive and reversible RF switch based on resistive switching effect observed in CBRAM memory. To maintain the on state or the off state no power is required, since as for a mechanical bi-stable switch, the on state is characterized by a real metallic bridge while the off state is related to the absence of this bridge. To switch on, a positive voltage up to 10V is necessary during few second to create the conductive filament, while a negative voltage is necessary to break it. To validate this new concept, a DC characterization has been conducted to determine the best way to switch between the two states. The transition has been characterized up to 0.15 GHz and an isolation of −20 dB with a insertion loss of −1.6 dB has been observed at 0.15GHz with a very simple design. To go further, a design of a switch able to operate up to 10GHz is presented.

On the mechanisms of cation injection in conducting bridge memories: The case of HfO2 in contact with noble metal anodes (Au, Cu, Ag)

In this work, tetrakis(dimethylamino)titanium precursor as well as in-situ oxidized ruthenium bottom electrode were used to grow rutile-structured titanium dioxide thin layers by plasma enhanced atomic layer deposition. Metal–insulator–metal capacitors have been elaborated in order to study the electrical properties of the device. It is shown that this process leads to devices exhibiting excellent results in terms of dielectric constant and leakage current.

A fully passive RF switch based on nanometric conductive bridge

This paper presents a new approach for the realization of RF switches based on the Conductive Bridging Random Access Memory technology (CBRAM). This promising approach allows the realization of RF switches in an extremely simple manner at low cost. For the first time, an RF switch based on a MIM structure is realized with an insulator layer obtained from a commonly used resin deposited by spin coating. The paper reports a RF switch based on CBRAM and demonstrates a device integration onto plastic circuit board (PCB). The realized switch is validated by experimental measurements for a frequency range up to 1.5 GHz with an activation voltage less than 1 V.

Rutile-structured TiO2 deposited by plasma enhanced atomic layer deposition using tetrakis(dimethylamino)titanium precursor on in-situ oxidized Ru electrode

We compare the switching behavior of two classes of resistive RAMs (RRAMs), namely Cu-SiO2 based conductive-bridging-RAMS (CBRAMs) and HfO2 based Oxide-RRAMs (OxRRAMs). In both devices the ON/OFF ratios are high, the set voltage is reproducible from cycle to cycle, and the reset voltage displays large dispersion. No forming stage is required in the investigated OxRRAMs. CBRAMs offer much lower programming voltage and current. The switching kinetics is limited by oxygen vacancy diffusion in OxRRAMs and by copper nucleation in CBRAMs.

Realization of a Conductive Bridging RF Switch Integrated onto Printed Circuit Board

In this paper, TiO2 layers grown on RuO2 by atomic layer deposition (ALD) using tetrakis (dimethyla-mino) titanium (TDMAT) and either oxygen plasma or H2O as oxygen source were analyzed using X-ray diffraction (XRD), Raman spectroscopy, and depth-resolved X-ray Photoelectron spectroscopy (XPS). The main objective is to investigate the surface chemical reactions mechanisms and their influence on the TiO2 film properties. The experimental results using XRD show that ALD deposition using H2O leads to anatase TiO2 whereas a rutile TiO2 is obtained when oxygen-plasma is used as oxygen source. Depth-resolved XPS analysis allows to determine the reaction mechanisms at the RuO2 substrate surface after growth of thin TiO2 layers. Indeed, the XPS analysis shows that when H2O assisted ALD process is used, intermediate Ti2O3 layer is obtained and RuO2 is reduced into Ru as evidenced by high resolution transmission electron microscopy. In this case, there is no possibility to re-oxidize the Ru surface into RuO2 due to the weak oxidation character of H2O and an anatase TiO2 layer is therefore grown on Ti2O3. In contrast, when oxygen plasma is used in the ALD process, its strong oxidation character leads to the re-oxidation of the partially reduced RuO2 following the first Ti deposition step. Consequently, the RuO2 surface is regenerated, allowing the growth of rutile TiO2. A surface chemical reaction scheme is proposed that well accounts for the observed experimental results.

Comparing the switching characteristics of two resistive RAM technologies: Cu-SiO 2 conductive-bridging-RAMs and HfO 2 Oxide-RAMs

Dielectric spectroscopy is carried out for intrinsic and aluminum-doped TiO2 rutile films which are deposited on RuO2 by the atomic layer deposition technique. Capacitance and conductance are measured in the 0.1u2009Hz–100u2009kHz range, for ac electric fields up to 1 MVrms/cm. Intrinsic films have a much lower dielectric constant than rutile crystals. This is ascribed to the presence of oxygen vacancies which depress polarizability. When Al is substituted for Ti, the dielectric constant further decreases. By considering Al-induced modification of polarizability, a theoretical relationship between the dielectric constant and the Al concentration is proposed. Al doping drastically decreases the loss in the very low frequency part of the spectrum. However, Al doping has almost no effect on the loss at high frequencies. The effect of Al doping on loss is discussed through models of hopping transport implying intrinsic oxygen vacancies and Al related centers. When increasing the ac electric field in the MVrms/cm rang...

Understanding the mechanisms of interfacial reactions during TiO2 layer growth on RuO2 by atomic layer deposition with O2 plasma or H2O as oxygen source

In this letter, the dielectric properties of rutile TiO2 thin films are studied for metal–insulator–metal capacitor applications. The dielectric constant, the ac conductivity, and the loss tangent are measured in a wide band frequency range, from 1 Hz to 2 GHz. The effect of aluminum doping, as well as the influence of film thickness, on the dielectric properties is presented.