Hiromasa Maruno

Focused ion beam direct deposition of gold

Focused ion beam direct deposition has been developed as a new technique for making patterned metal film directly on substrates. The 20 keV Au+ ion beam is focused, deflected, and finally decelerated to 30–200 eV between the objective lens and substrate. The decelerated beam is deposited on the substrate at room temperature. The beam diameter can be tuned between 0.5 and 8 μm and the beam current varies from 40 pA to 10 nA, corresponding to the beam diameter. Current density was about 20 mA/cm2, so that the deposition rate in the beam spot was estimated about 0.02 μm/s. The purity of gold film was measured with Auger electron spectroscopy and contents of carbon and oxygen, undesirable impurities, were below detection limits. The resistivity was constant at 3.7±0.1 μΩ cm for deposition over the ion energy range of 34–194 eV.

Focused ion‐beam direct deposition of metal thin film

Focused ion‐beam direct deposition has been developed as a new method for fabricating patterned metal films directly on substrates. The principle of this method is to perform ion‐beam deposition by low‐energy focused ion beams. We designed and constructed a low‐energy focused ion‐beam apparatus for direct deposition. Metal ions are extracted from liquid metal ion source, accelerated to 20 keV for single charged ions, focused, mass separated, deflected, and finally, decelerated to 30–1000 eV in this system. The beam diameter estimated by the deposited linewidth can be tuned between 0.5 and 8 μm and the beam current varies from 40 pA to 10 nA corresponding to the beam diameter for the Au+ ion in the energy range from 30 to 200 eV. The sticking probabilities of ion‐beam deposition were measured and the critical energies for Au+, Cu+, Al+, and Nb2+ were about 210, 230, 800, and 1300 eV, respectively. The purity of gold film was measured by Auger electron spectroscopy and secondary‐ion‐mass spectroscopy. The c...

Focused ion beam direct deposition of superconductive thin film

Focused ion beam direct deposition of niobium has been developed as a technique for fabricating superconductive thin films. A Nb2+ ion beam extracted from a Nb10–Au50–Cu40 liquid metal ion source was accelerated to 40 keV, focused, deflected and finally decelerated to 50–1000 eV. The beam current density was 0.4–2 mA/cm2 and the minimum deposited linewidth was about 0.5 μm. The sticking probability of the Nb2+ ion beam and the critical temperature of deposited niobium films were measured. The deposition at different deposition rates and different residual gas pressure were performed. A clear relation was obtained between the critical temperature and the concentration of contaminations. This relation is consistent with the published relation for bulk niobium if it is assumed that the sticking probability of residual gas is 0.2. However, dependence of the critical temperature on ion energy was not observed.

Color video camera capable of 1,000,000 fps with triple ultrahigh-speed image sensors

We developed an ultrahigh-speed, high-sensitivity, color camera that captures moving images of phenomena too fast to be perceived by the human eye. The camera operates well even under restricted lighting conditions. It incorporates a special CCD device that is capable of ultrahigh-speed shots while retaining its high sensitivity. Its ultrahigh-speed shooting capability is made possible by directly connecting CCD storages, which record video images, to photodiodes of individual pixels. Its large photodiode area together with the low-noise characteristic of the CCD contributes to its high sensitivity. The camera can clearly capture events even under poor light conditions, such as during a baseball game at night. Our camera can record the very moment the bat hits the ball.

An ultrahigh-speed video camera and its applications

We have developed an ultra high-speed video camera announced by Etoh at the 24th ICHSPP. This new camera can capture 100 continuous images with a frame rate of up to 1,000,000 frames per second (fps). It comprises a new developed single-chip CCD image sensor called In-situ Storage Image Sensor (ISIS). The spatial resolution is 312 x 260 pixels and this high resolution is kept even at the maximum frame rate. This camera enables us to observe the fast phenomena, which could not be seen before. The principle of this system and some applications are introduced.

Low-energy focused ion-beam system for direct deposition

Low energy focused ion beam direct deposition has been developed as a new method for fabricating patterned metal films directly on substrate. The principle of this technique is to perform ion beam deposition by using a very low energy focused ion beam. A low energy focused ion beam system for direct deposition has been designed and constructed. In this system the desired material is ionized, separated from undesired ion species, focused, deflected, and decelerated to the optimum deposition energy. The main components of the system are a liquid metal ion source, a mass filter, two Einzel lenses, double octapole deflectors, and an electrically floating sample stage. The beam energy can be continuously varied from 0 eV to 20 keV for single charged ions. The beam diameter can be tuned between 0.5 and 8 micrometers and the beam current varies from 40 pA to 10 nA corresponding to the beam diameter for Au+ ion in the energy range from 30 eV to 200 eV. The purity of deposited gold film was measured by Auger electron spectroscopy and concentrations of carbon and oxygen were below detection limits. The resistivity of gold film was 3.7 +/- 0.1 (mu) (Omega) cm. Currently, new applications of this deposition method are being developed.

Optical properties of a low energy focused ion beam apparatus for direct deposition

We designed and constructed a low energy focused ion beam apparatus for direct deposition. The optical properties of our lens system were calculated to obtain its optimum shape and arrangement for a low energy (50–100 eV) and fine focused (<1 μm) ion beams. We evaluated magnification, chromatic aberration, and spherical aberration. Using the apparatus based on our design, we deposited a focused ion beam and deduced the beam diameter from linewidth measurement of the deposited film. The diameter of 50–200 eV Au+ beams could be tuned between 0.4–7 μm corresponding to beam currents of 40 pA–10 nA. The current density was constant at about 30 mA/ cm2. At lower currents, the minimum beam diameter was limited to 0.35 μm. These experimental results agree with calculated results qualitatively, but quantitative differences exist. Assumptions, based on Ga+ ion sources, seem to cause the differences. If we adopt our measured energy dispersion (30 eV) and angular current density (10 μA/sr) and assume the virtual sour...