Application

Author: N. NAKA; T. SHIMIZU; H. BABA; T. NUMATO; J. AOYAMA; S. AWATA; T. HATAYAMA – Nobuyuki NAKA, Tomoya SHIMIZU, Hiroki BABA, Tomoko NUMATO, Junichi AOYAMA, Shogo AWATA and Tomoaki HATAYAMA Power devices using Silicon Carbide (SiC) are already commercialized and are moving into mass production, but commercial SiC wafers have several types of defects. It is important to have techniques for analyzing a variety of defects, because these defects decrease the yield ratio of SiC devices. In this paper, we did complex analysis on sub-millimeter- and nanometer-scale defects and stress in epitaxial / bulk SiC wafers. The laser scattering method can detect submicronsized defects on the entire surface of a 4-inch (10.16 cm) wafer in about 3 minutes. Our original CathodeLuminescence (CL) imaging system can evaluate nanometer-sized crystal defects using a submillimeter-scale panchromatic image acquired in a short time, and PhotoLuminescence (PL) lifetime measurements help us understand carrier lifetime. Furthermore, we show that Raman spectroscopy can evaluate stress distribution around defects detected in CL images in a non-destructive manner.

Author: Hisashi YAMANOUCHI – The concentration of calcium in food samples is commonly measured by use of Inductively Coupled Plasma (ICP), Ion Chromatography (IC) and Atomic Absorption Spectrophotometry (AAS). However, these methods are not appropriate for on-site measurement at production lines and farms because these instruments are too large to carry out. In this paper, we propose new measurement method which dissociates the compound including calcium into the calcium ion adjusting pH of samples before the potentiometric measurement with the compact calcium ion meter (abbreviated as Ca2+-meter). The results obtained by use of Ca2+-meter with pretreatment were good agreement with that obtained by use of ICP. We can measure all amount of calcium in milk products by use of Ca2+-meter with pretreatment which generate free calcium ions from the calcium compound in milk products.

Author: Manabu SHIBATA – It is difficult to measure accurately and quickly pH of low conductivity solutions by use of pH glass combination electrodes based on a KCl salt bridge (KClSB). The reasons are the variation of the liquid junction potential (LJP) between a KClSB and a sample solution, and the change of pH in the sample solution due to the leakage of the concentrated KCl from the liquid junction. In order to solve the intrinsic problems, a new reference electrode, where an ionic liquid was used as the material of liquid junction, has proposed. The pH glass combination electrode equipped with an ionic liquid salt bridge (PUREIL electrode) enables us to measure accurately and quickly pH of less than 10 mS m-1 sample solutions such as pure water and boiler water. In this paper, we show the pH measurement of 10 mS m-1 sulfuric acid solution by use of PUREIL electrode.

Author: Kenji HARA; Montajir RAHMAN – Nitrous Oxide (N2O) emission reduction has gained large prominence recently due to its contribution to the climate change as a greenhouse gas. The United States Environment Protection Agency (EPA) together with the United States Department of Transport (DOT) has already regulated the N2O emissions from Light-Duty Vehicles (LDV). For LDV, N2O measurement should be done from sample storage bags over the light-duty FTP drive cycles. N2O emission standard of 0.10 g/bhp-hr for Heavy-Duty Engines (HDE) is also finalized. The final N2O standard becomes effective in 2017 model year for diesel engines. Usually raw or diluted exhaust is measured for HDE emission testing. Therefore, an analyzer capable of measuring N2O from bag and from diluted sample continuously is required to support both LDV and HDE regulations. In this study, comparative measurement of automobile exhaust N2O in continuous dilute and in sample storage bag has been attempted. A modern vehicle meeting 2008 Japanese emission standards has been evaluated. In this letter, it is found that the laser based exhaust gas analyzer has sufficient detection capability for bag measurement and fast response for continuous dilute measurement.