Hironori Tanaka

Sm-doped CsBr crystal as a new radio-photoluminescence (RPL) material

Abstract Radio-photoluminescence (RPL) is a phenomenon seen in luminescent materials in which the appearance of new photoluminescence (PL) emission is induced by an incident ionizing radiation such as X-rays; and the signal is stable even after the irradiation and during the PL measurement. Since the induced PL intensity is proportional to the irradiation dose, the RPL can be used in radiation measurements. The distinct advantage of RPL over the conventional thermally- or photo-stimulated luminescence (abbreviated as TSL or PSL) dosimeters is the stability of response signal. With an RPL detector, it allows us to readout the signal multiple time without signal fading. In this work, we discovered that CsBr:Sm showed an RPL phenomenon by X-ray irradiation, and we characterized this new material as an RPL detector. While the sample showed PL emissions mainly in the visible range, after an X-ray irradiation additional emissions could be observed in the red to near-infrared range around 650–850 nm and 900–1000 nm and longer. The RPL response was fairly stable overall, but very interestingly the 650–850 nm signal slightly increased while the 900–1000 nm decreased during PL readout. The dynamic range was confirmed over 1–104 mGy with linear response.

Advanced Method for Measuring Ultra-Low Contact Resistivity Between Silicide and Silicon Based on Cross Bridge Kelvin Resistor

In order to evaluate low contact resistivity precisely, we have developed a new test structure based on cross bridge Kelvin resistor. In this structure, the misalignment margin can be as small as possible. Furthermore, we had successively derived the theoretical expressions to ensure the validity of the newly developed method. This method will enable us to evaluate the silicide to silicon contact resistivity in the sub-10-8 ¿cm2 region.

Photoluminescence and radiation response properties of Ce3+-doped CsCaCl3 crystalline scintillator

In this paper, we report on the photoluminescence and scintillation properties of a newly developed CsCaCl3:Ce (0.5 mol%) crystalline scintillator grown by the vertical Bridgman method. The fluorescence quantum efficiency for the Ce3+ characteristic emission bands centered at around 350–400 nm was 76% under excitation at 330 nm light. The photoluminescence decay time of the Ce3+ was approximately 32 ns. When x-ray excited the crystal, intense emission bands were observed at 350–400 nm, and could be attributed to the Ce3+ emission. The scintillation light yield of the developed crystal was ~7600 ph MeV−1 compared to a NaI:Tl commercial scintillator, and the principal scintillation decay time was approximately 340 ns plus two fast components of around 1.6 ns and 45 ns.

Impact of Tungsten Capping Layer on Yttrium Silicide for Low Resistance Source/Drain Contacts

Source/drain parasitic resistance RSD of MISFETs is a serious problem because it will limit their performance when the current drivability increases sufficiently. In order to reduce RSD, it is important to reduce contact resistance. As the Schottky Barrier Height (SBH) between silicide and silicon must be low to achieve low contact resistivity [1], a dual silicide structure, using low work function silicides for n silicon and high work function silicides for p silicon, is a promising solution [2]. However, it is difficult to obtain low SBH for electrons because it requires handling low work function metals, which are easily oxidized in air. Therefore, the oxidation prevention technology is indispensable. In this paper, we investigated the physical and electrical properties of tungsten/yttrium stack.

Three-Dimentional Optical Storage Medium Using Arranged Nano-spheres

In this study, we have developed a multi-layered optical storage medium with nano-spheres as the recording medium. We made a three-layered medium of spheres and thereby realized a three-dimensional high-density optical storage system. Using a reflection confocal optical system, we read out clock signals from the medium. The system records data and reconstructs it jitter-free.