Koichiro Hattori

Thermal Conductivity of Amorphous Indium–Gallium–Zinc Oxide Thin Films

We investigated the thermal conductivity of 200-nm-thick amorphous indium–gallium–zinc-oxide (a-IGZO) films. Films with a chemical composition of In:Ga:Zn= 1:1:0.6 were prepared by dc magnetron sputtering using an IGZO ceramic target and an Ar–O2 sputtering gas. The carrier density of the films was systematically controlled from 1014 to >1019 cm-3 by varying the O2 flow ratio. Their Hall mobility was slightly higher than 10 cm2V-1s-1. Those films were sandwiched between 100-nm-thick Mo layers; their thermal diffusivity, measured by a pulsed light heating thermoreflectance technique, was ~5.4×10-7 m2s-1 and was almost independent of the carrier density. The average thermal conductivity was 1.4 Wm-1K-1.

Simple digital phase-measuring algorithm for low-noise heterodyne interferometry

We present a digital algorithm for measuring the phase difference between two sinusoidal signals that combines the modified fringe-counting method with two-sample zero crossing to enable sequential signal processing. This technique can be applied to a phase meter for measuring dynamic phase differences with high resolution, particularly for heterodyne interferometry. The floor noise obtained from a demonstration with an electrical apparatus is

Final report on Supplementary Comparison APMP.M.H-S1

5\times10^{-8} \mathrm{rad/\sqrt{Hz}}

Oxidation Resistance of Ti–Si–N and Ti–Al–Si–N Films Deposited by Reactive Sputtering Using Alloy Targets

at frequencies above approximately 0.1 Hz. In addition, by applying this method to a commercial heterodyne interferometer, the floor-noise level is confirmed to be

Hardening Mechanisms of Amorphous / Polycrystalline Nanostructured Multilayer Films: Si3N4/CrN and Si3N4/TiN

7\times10^{-14} \mathrm{m/\sqrt{Hz}}

Microstructure and properties of CrN/Si3N4 nano-structured multilayer films

from 4 kHz to 1 MHz. We also confirm the validity of the algorithm by comparing its results with those from a standard homodyne interferometer for measuring shock-motion peak acceleration greater than 5000 m/s^2 and a 10 mm stroke.

Bandwidth-tunable frequency counter

This report presents the results of supplementary comparison APMP.M.H-S1 among four national metrology institutes (NIMT, NMIJ/AIST, VMI and SPRING). The comparison was carried out during October 2004 to January 2005 in order to determine the capability of the primary Rockwell hardness standard, including standard conditions, of each participant, to confirm the accuracy of Rockwell hardness scale C measurement declared by the participant, which includes the effect of each participants primary indenter and determine the degrees of equivalence of hardness scale measurement in the range 20 HRC to 60 HRC. Furthermore, the comparison was carried out a by common indenter, which was provided by the pilot institute, in order to determine the measurement capability of the participants primary machine without the influence of the indenter, as a study of scientific purpose. The pilot institute was the National Institute of Metrology (Thailand), NIMT. There were two sets of artifacts for the comparison. Each set was composed of nine hardness blocks: 20 HRC, 25 HRC, 30 HRC, 35 HRC, 40 HRC, 45 HRC, 50 HRC, 55 HRC, 60 HRC. The verification of the participants primary Rockwell hardness machine was carried out according to ISO6508-3 before making the measurement. The pilot institute made measurements at the beginning and the end of the comparison in order to monitor the stability of the artifacts. The degree of equivalence of each national primary hardness standard was expressed quantitatively by two terms, the deviation from KCRV and the uncertainty of this deviation at a 95% level of confidence. The En parameter was calculated to express the equivalence between the measurements of participants as well. The degree of equivalence between pairs of participating institutes was expressed by the difference of their deviations from the key comparison reference value and the uncertainty of this difference at the 95% level of confidence. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the APMP, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Development of high-speed automatic birefringence measurement apparatus using the new small Mach-Zehnder interferometer

Ti–Si–N and Ti–Al–Si–N films, which possess high hardness due to the formation of a nanocomposite structure in the films, were deposited by reactive magnetron sputtering using alloy targets and then postannealed in air at temperatures ranging from 300 to 800 °C. The hardness of both the films decreased significantly as postannealing temperature increased. However, the hardness of Ti–Al–Si–N films postannealed up to 500 °C remained at more than 30 GPa, which was significantly higher than that of the Ti–Si–N films after the post annealings. Electron probe microanalyses and X-ray photoelectron spectroscopy revealed that Al2O3 phases were formed in the postannealed Ti–Al–Si–N films. Transmission electron microscopy with energy-dispersive X-ray analysis showed that the Al2O3 layer of the postannealed Ti–Al–Si–N films was formed 40 nm below the surface, whereas the depth of the TiO2–SiO2 layer of the postannealed Ti–Si–N films was 100 nm from the surface. These results indicate that Al2O3 phases existed at the surface of the Ti–Al–Si–N films and prevented the oxidation of the interior of the films during postannealing at high temperatures in air.

Evaluation of indentation modulus considering elastic anisotropy

The amorphous/polycrystalline Si 3 N 4 /CrN and Si 3 N 4 /TiN nano-structured multilayer films have been fabricated by RF reactive magnetron sputtering. The microstructure and properties of these films were measured by XRD, HRTEM and nano-indenter There is no superhardness effect in the Si 3 N 4 /CrN multilayers. The hardness values of Si 3 N 4 /CrN multilayers are between those of the constituent CrN and Si 3 N 4 films at a substrate temperature of 20∼C, and are a little higher than those of Si 3 N 4 films at a deposition temperature of 500°C. However, the superhardness effect was found in Si 3 N 4 / TiN multilayers. The hardness of Si 3 N 4 / TiN multilayers is affected not only by modulation periods, but also by layer thickness ratio and deposition temperature. The maximum hardness value is about 40% higher than the value calculated from the rule of mixtures at a deposition temperature of 500°C and a layer thickness ratio ( l Si3N4 / l TiN ) of 3 / 1. Based on experimental results, the hardening mechanisms in these multilayers have been discussed.