Integration of light sources on a Si chip is one of milestone to establish new paradigm of LSI systems, so-called "silicon photonics." In recent years remarkable progress has been made in the Si wire waveguide technologies for optical interconnection on a Si chip. In this paper, several Er embedded materials based on silicon are surveyed from the standpoint of application to the light emission and amplification devices for silicon photonics. We have concentrated to investigate an erbium silicate (Er2SiO5) as a light source medium for silicon photonics. To mention the particular features, this material has a layered structure with 0.86-nm period and a large amount of Er (25at%) as its constituent. The single crystalline nature gives several remarkable properties for the application to silicon photonics. We also discuss our recent studies of Er2SiO5 and a possibility of the shorter waveguide amplifier.

We focus on the development of new silicate phosphors for a white LED. In the europium doped silicate system, four LED phosphor candidates-- Li2SrSiO4:Eu2+, Ba9Sc2Si6O24:Eu2+ , Ca3Si2O7:Eu2+ and Ba2MgSi2O7:Eu2+ were found. Luminescent properties under near UV and visible excitation were investigated for the new Eu2+ doped LED silicate phosphors. These new phosphors have a relatively strong absorption band in a long wavelength region.

Thermal stability of stacked high-κ dielectrics, especially ZrO2, HfO2 and ZrSiO4 /SiO2 layered structures, on silicon has been investigated in terms of ultrahigh vacuum (UHV), 1 Torr N2 and helium (He) gas annealing with controlled oxygen partial pressure (PO2) at 920. Comparison of 2 nm and 20 nm ZrO2 films under UHV annealing revealed that the trigger of silicidation is the contact of ZrO2, SiO and Si accompanying disappearance of interfacial SiO2 layer due to SiO desorption. In the contact position, a small amount of SiO gas can easily change ZrO2 to ZrSi2. This reaction model is also applicable to the silicidation of HfO2 and ZrSiO4, at not only stacked high-κ film/Si substrate interface, but also at gate poly-Si/high-κ film interface. Moreover, comparison of UHV, N2 and He annealing with controlled PO2 revealed that the optimal PO2 ranges in He at which the thermal stability of layered structure can be achieved are wider than those in UHV and N2. This result suggests that He gas physically may obstruct SiO creation due to the quenching of atomic vibration at degradation-prone sites in the SiO2 /Si interface, thus reducing probability of bond breaking process, which is the first step of silicidation.

The mesoporous materials from the self-assembled organic-inorganic compound materials have great possibilities for a variety of applications. However, to make use of these kinds of materials effectively, they must be controlled. In this paper, we are succeeded in powder state pore size control and in significantly fabrication film state for device application use.

Self-ordered mesoporous silicate films from organic-inorganic compound materials are successfully fabricated into the surface photo voltage (SPV) type gas sensor device as a gas adsorption insulator layer. These kinds of gas sensors device exhibit NO gas sensing property dependent on their mesoporous film structure. We are succeeded in indication about a possibility of mesoporous silicate film for the SPV type gas sensor application.

We propose low Rayleigh scattering Na2O-MgO-SiO2 (NMS) glass as a candidate material for low-loss optical fibers. This glass exhibits Rayleigh scattering which is only 0.4 times that of silica glass, and a theoretical evaluation suggests that it is dominated by density fluctuation. An investigation of the optical properties of NMS glass reveals that a minimum loss of 0.06 dB/km is expected at a wavelength of 1.6 µm and that the zero-material dispersion wavelength is found in the 1.5 µm band. To establish the waveguide structure, we evaluated the feasibility of using F-doped NMS (NMS-F) glass as a cladding layer for an NMS core and found that it is suitable because it exhibits low relative scattering (e.g. 0.7) and is versatile in terms of viscosity matching. We also describe an attempt to draw optical fibers using the double crucible technique.