We fabricated copper (Cu) thin films on a glass substrate using magnetron sputtering with multipolar magnetic plasma confinement (MMPC) method. MMPC sputtering deposition technique is powerful method to be able to fabricate high quality thin film by the effect of ion irradiation so that plasma is transported to the substrate along magnetic lines of force formed by permanent magnets arranged on the sides of the target. In order to obtain the knowledge on the effects of ion irradiation, RF power (PT) dependence on structural and electrical properties of Cu thin films fabricated by MMPC method was investigated. For the deposition conditions, we changed PT in the range of 30-100 W under an Ar gas pressure (PAr) of 0.1 Pa. The film thickness was set to about 200 nm. From plasma emission spectroscopy, Ar ion density increased as PT increased. AFM image analysis revealed that the average surface grain size of the fabricated Cu thin films surface was almost constant as PT increased and was not significantly enhanced by ion irradiation. However, surface diffusion was promoted as PT increased and the film surface became smooth. From the XRD spectrum analysis, the crystallite size of fabricated Cu thin films changed as PT increased. From this result, we found that the effect of ion irradiation affect the film density. The resistivity of fabricated Cu thin films was dependent on the surface morphology and crystal structure affected by the change in the effect of ion irradiation. The minimum resistivity of the Cu thin film was 1.763 µΩcm at a PT = 100 W and PAr = 0.1 Pa. In this study, effective surface diffusion for high quality thin film formation was performed using only the effect of ion irradiation without heating substrate. We confirmed the possibility to fabricate Cu thin film with resistivity comparable to the bulk value. We concluded that this sputtering method was effective for high quality thin film formation.
In this work we present the use of a transparent thin film transistor (tTFT) substrate to perform non-mutative cell viability measurements through purely electrical means. This is done through the measurement of the impedance of a region of the cellular culture and monitoring its change. By mapping this with simultaneous fluorescent measurements we managed to build predictive models for cell viability that obviate the need for mutative dyes while still enabling their use for simultaneous or subsequent measurement.
This paper reports on moment detection by three integrated tactile sensors that detect 3-axis forces. In this study, the three integrated tactile sensors were connected along a serial bus and were mounted in a triangle shape on a circuit board. Out-of-plane moment applied on the circuit board was measured using the shearing forces and a geometric relationship of the triangle sensor allay. The principle of the proposed moment detection method was demonstrated. The experimental results showed that the sensitivity and the nonlinearity were 1.10 count/N·m and ±16% full scale, respectively. The resolution of the obtained moment was below 0.015 N·m. The moment detection ability enables the partner robots to grasp objects correctly and to interact softly with human.
In this study, suspended micro-heater using TiN for decreasing power dissipation was fabricated and evaluated. The self-supporting film of the suspended filament was developed by the low compressive stress SiO2 film deposited by the dc reactive sputtering method with rf substrate bias and the post annealing at 900℃. In the suspended structure process, single photolithography process and two wet etching process of HF and KOH solution were used. The power dissipation of the suspended heaters was obtained about 70mW and it is indicated that the power dissipation is able to reduce than the other structure in previous research. Then, it is expected that the TiN micro-heater using suspended structure is applicable to several MEMS sensors.
In Japan, many people live in mountainous area and sometimes they experienced landslides under heavy rain. Also there are many superannuated constructions which built at 1960-70's. Wide area monitoring systems which can detect critical conditions are useful to prevent disasters. This study proposes new fiber optic loss variation measurement system which can use for wide area installed branched fiber networks. It can detect local strain variation in combination with appropriate sensors. This paper proposes new fiber optic sensing systems using different length fiber branches. If some transmission loss was induced anywhere on branched fibers, the Rayleigh backscattering signal response would be changed. We can detect where and how much the loss induced. The simulation and experiments have done using 2 branched fiber networks. The experimental results using OTDR (Optical Time Domain Reflectometer) have good agreements with simulation results. We can calculate the loss value and its position backward from the Rayleigh back scattering signal response.