• Toward the ultimate performances of image sensors, advanced research activities are being conducted that cover a wide range of technology fields from cleanroom infrastructure, materials, process equipment, process, device, circuit, assembly, signal processing, measurement/evaluation and reliability. Following technologies have been successfully commercialized:
• A fast and accurate measurement technology of electrical characteristics for over 1 million transistors
• A wide dynamic range CMOS image sensor technology capturing images over five decade brightness ranges
• An ultra-fast CMOS image sensor technology with 10 million frames/sec

Followings are available for industry collaborators:
A. 200mm-diameter-wafer silicon device fabrication utilizing the ultra-clean facility including wafer mutual fabrication processing between device manufacturers.
B. Process technology development and various kinds of analyses.
C. Development of new image sensors.

• Scanning tunneling microscope (STM) and atomic force microscope (AFM) are among a few microscopes which enable a direct observation of atomic scale structures of materials. If compared with other electron microscope like transmission electron microscope (TEM), the energy of the electron used for STM is very low that has a big advantage of low damage for sample. Thus STM and AFM are regarded as the most important tools to characterize materials in nanotechnology. The research is now developing from a mere observation of the shape of material to the characterization specific properties of materials with an atomic scale resolution. These properties include spin and molecule vibration; well established techniques like ESR/NMR and infrared-spectroscopy requires more than billions of molecules to obtain data, while STM can obtain these data for a single molecule.
• We are interested following issues and like to have a collaboration with industrial companies.
• 1. Molecule-scale morphological characterization of soft-material, polymers and bio material.
• 2. Site specific vibration spectroscopy of molecules with an atomic resolution.
• 3. Single spin detection with ESR-STM method
• 4. Developing atom-scale characterization tool

• We found an effective catalyst system composed of CeO2 and 2-cyanopyridine for direct and catalytic polycarbonate formation reaction from CO2 and diols. CeO2 acted as an activator for CO2 and diols, and 2-cyanopyridine shifted the equilibrium in favor of the product side by hydration of 2-cyanopyridine, promoting the reaction. Green polycarbonates can be synthesized by combination of the catalyst system with a technique of diol syntheses from biomass.

This catalyst system is effective for direct transformation of CO2, contributing to the effective utilization and emission reduction of CO2. Combination of the catalyst system with a concentration technique of CO2 will bring about much advantage.

• The main research subject of our group is developing material purification methods, crystal growth methods and detector fabrication technologies for compound semiconductor radiation detectors. Our group intensely studies a compound semiconductor, thallium bromide (TlBr), for fabrication of gamma-ray detectors for the advanced radiation applications. The attractive physical properties of TlBr lie in its high atomic number (Tl: 81, Br: 35), high density (7.56 g/cm3) and wide bandgap (2.68 eV). Due to the high atomic number and high density, TlBr exhibits high photon stopping power. The wide bandgap of TlBr permits the device low-noise operation at and above room temperatures.

Our group focuses on development of compound semiconductor radiation detectors for advanced radiation applications including ultra-high resolution PET systems, ultra-high resolution SPECT systems, photon counting CT systems and Compton cameras. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• One of the important challenges in the development of carbon nanotubes (CNTs) reinforced ceramic composites is uniform dispersion of CNTs in the matrix. The mechanical properties of CNT/ceramics composites have been limited to date due to the formation of CNT agglomerates in the composite. We have successfully produced CNT/alumina composites with world top class strength and toughness, by employing a newly developed CNTs dispersion technique based on a flocculation method. The processing method developed in this study enables us to prepare high performance CNT materials using a pressureless sintering method.

The possible applications of the CNT/alumina composites developed in this study include tribological materials (ball bearing), biomaterials (artificial hip joint), micro-actuator materials utilizing electrostrictive effects, electromagnetic wave absorber, particularly in the frequency range of several GHz and several ten GHz.

• Recently, many tunnel magnetoresistance devices with high magnetoresistance effect are reported. These are expected to be applied to high sensitive magnetic sensors. There are many magnetic sensors with variety of the mechanism, in order to meet the demand of the very wide range of sensing magnetic field. However, there is no magnetic sensor which has high sensitivity, easy to use, operation at room temperature and low cost. Only a magnetic sensor with tunnel magnetoresistance devices can satisfy all the demand in principle. As the device has very wide range of the sensing magnetic field, it can be designed for any demand to the sensors.

For example, this device can sense a bio-magnetic field easily at room temperature, so that it could be replaced SQUID device, which is popular now but is very expensive and not easy to use personally. Therefore, by using this device, we expect we can conduct effective collaborative research in medical field.

• Electronic products can be operated not only by semiconductors but also by metal interconnections attached to the semiconductors. Required properties for the metal interconnections are ohmic contact, diffusion barrier property, adhesion with semiconductors, and low resistivity, corrosion resistance, process reliability. Our group has committed ourselves to develop new metals and processes to meet the needs of wide-ranged device producers with consideration of cost performance. Topics of our research include (1) Cu alloys to self-form a diffusion barrier layer in multilayer interconnection of Si devices, (2) Cu alloys to form a reaction-doping layer in IGZO oxide semiconductors, (3) Nb alloys to achieve mechanical and thermal reliability with good ohmic property for SiC power devices, (4) Cu alloys for transparent conductive oxide such as ITO, (5) screen-printable Cu paste lines for solar cells, etc..

Our research efforts are targeted at metallization and interconnections for advanced LSI, flat panel displays, touch panels, power modules, solar cells, and other electronic devices. Collaborators include material producers, equipment vendors, and device producers in the entire value chain of electronic products.