K. Natori

Physical and electrical properties of ultra-thin nickel silicide Schottky diodes on Si (100)

The physical and electrical properties of Ni silicides, reactively formed by a thin Ni layer of 3 nm, have been investigated. The existence of NiSi2 phase has been confirmed at low temperature annealing by x-ray photoelectron spectroscopy. The silicides have shown flat surfaces up to an annealing temperature of 800 °C and a stable sheet resistance can be achieved. The Schottky barrier heights extracted from diode characteristics have shown stable values against annealing temperature owing to the stability of the film with an ideality factor nearly to unit.

Influence of Structural Parameters on Performance of Schottky Tunneling FET Electrical Characteristics and its Scalability

1 Frontier Research Center, Tokyo Institute of Technology, 2 Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan 3 Honors Graduate Program for Nanotech/Sciences, University of Tsukuba, 4 Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan 5 Institute for Nanoscience and Nanotechnology, Waseda University Shinjuku, Tokyo 169-8555, Japan Phone: +81-45-924-5847, Email: yan.w.ab@m.titech.ac.jp

Individual Atomic Imaging of Multiple Dopant Sites in As-Doped Si Using Spectro-Photoelectron Holography

The atomic scale characterization of dopant atoms in semiconductor devices to establish correlations with the electrical activation of these atoms is essential to the advancement of contemporary semiconductor process technology. Spectro-photoelectron holography combined with first-principles simulations can determine the local three-dimensional atomic structures of dopant elements, which in turn affect their electronic states. In the work reported herein, this technique was used to examine arsenic (As) atoms doped into a silicon (Si) crystal. As 3d core level photoelectron spectroscopy demonstrated the presence of three types of As atoms at a total concentration of approximately 1020 cm-3, denoted as BEH, BEM, and BEL. On the basis of Hall effect measurements, the BEH atoms corresponded to electrically active As occupying substitutional sites and exhibiting larger thermal fluctuations than the Si atoms, while the BEM atoms corresponded to electrically inactive As embedded in the AsnV (n = 2-4) type clusters. Finally, the BEL atoms were assigned to electrically inactive As in locally disordered structures.

Influence of sputtering gas on resistivity of thin Ni silicide films

Ni silicide film, formed by stacked structure of nickel and silicon, have been fabricated by RF magnetron sputtering using different gas species. The resistivity of the silicide films have been measured. While the resistivity of the film with Ar gas sputtering gradually decreases with higher annealing temperature, films with Kr gas sputtering show resistivity as low as the bulk ones in a wide process-temperature window. A model to explain the mechanism difference has been proposed.

An investigation of CeO 2 based ReRAM with p + and n + -Si bottom electrodes

In this paper we use the p⁺-Si and n⁺-Si as bottom electrode for CeO₂ based ReRAM. The work function difference between p⁺-Si and n⁺-Si substrate gives out an about 0.6 V shift of the set and reset voltage. The mechanism of this shift was investigated and the set and reset of voltage with pulse width dependence was also concerned depends on p⁺-Si substrate.

Electrical analyses of nickel silicide formed on Si nanowires with 10-nm-width

Ni silicide with the nanowire line width down to 15 nm was formed by the reaction of Ni thin films with Si nanowires. The electrical analyses revealed that Ni2Si was formed on all Si nanowires having width in the range from 15 to 80 nm. However, a drastic increase in the resistivity was observed for the width smaller than 35 nm. The reason for this increase is discussed in terms of roughness in line width and electron scattering on the surface of nanowires.

A Proposal of a Forming-Free Resistive Switching Memory based on Breakdown and Anodic Reoxidization of thin SiO2 on NiSi2 Electrode using CeOx Buffer Layer

A novel forming-free resistive memory with a large ON/OFF ratio of 10 is proposed based on breakdown and anodically reoxidized thin SiO2 layer using CeOx buffer layer and silicide electrodes. Low resistive state (LRS) is achieved by hard breakdown of the thin-SiO2 layer owing to high dielectric constant of the CeOx layer. By applying opposite bias to the electrode, high resistive state (HRS) can be reverted back by local anodic oxidation of the breakdown spot by high oxygen ion conductivity of CeOx layer.