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Field survey for the 2003 Tokachi-oki earthquake tsunami was conducted by the scientists from all over Japan [Tanioka et al., 2004a, b]. Large tsunami heights of about 4 m were observed at Hyakuninhama to the east of Cape Erimo and along the beach between Horokayanto and Oikamanai. Those places are close to the source region of the earthquake. In general, tsunami heights gradually decreased to the east and to the west away from those two locations except at Mabiro where a large tsunami height of about 4m was locally observed. The most intensive tsunami survey was conducted at the Ootsu harbor. The survey results indicate that the quay of the harbor was completely submerged by the tsunami, but the road around the harbor was not. Numerical computation of the 2003 Tokachi-oki tsunami was carried out by solving the nonlinear shallow water equations with a moving boundary condition near the Ootsu harbor. The computed tsunami at the Ootsu harbor well explains the above observations.

Switching phenomena with current‐control‐type negative resistance characteristics were observed in thin‐insulator metal‐insulator‐semiconductor diodes made on n‐type (100) silicon substrates. The characteristics except breakover point are reproducible and the diodes are also switched from a low‐conduction state into a high‐conduction state under a fixed‐bias condition by light stimulation from a commercial light‐emitting diode. One of the possible origins of this negative resistance is carrier multiplication by high‐energy electrons tunneled through the thin insulator and injected into the surface of the n‐type silicon substrate.

A patient who died of hepatic failure nearly 29 years after hepatic portojejunostomy is reported. His death may be attributed to several faults in treatment. From our experiences it can be said that biliary atresia is a curable disease, although liver-transplantation is required in some patients in whom hepato portoenterostomy is unsuccessful.

A pnp-type GaAs inversion-base bipolar transistor was fabricated for the first time. The common emitter current gain obtained was β=1010 at 77 K. By measuring the FET mode operation of the GaAs IBT, it was confirmed that the two-dimensional electron gas really worked as a base of the transistor.

A low-temperature pretreatment of a crystalline silicon substrate for solid-phase epitaxy of a CVD a-Si film on the substrate was studied. It was found that chlorine mixed with hydrogen etches the surface of the silicon substrate at a reduced pressure and a low temperature, e.g. 540°C. This low-temperature etching process was used as an in-situ surface cleaning process prior to CVD of an a-Si film on the silicon substrate at the same temperature. Vertical and lateral solid-phase epitaxial (L-SPE) growth was successfully obtained with this in-situ pretreatment. Using this L-SPE film, XMOS transistors were fabricated.

Light-soaked states in hydrogenated amorphous silicon (a-Si:H) are not recovered by near-infrared or visible light illumination. Simple trapping of photogenerated carriers in the gap states of a-Si:H can, thus, be ruled out as the main process which initiates the light-induced changes. The carrier trapping accompanying the change in the atomic configuration, on the other hand, cannot be excluded as the initial process of the changes. The illumination on the light-soaked states may induce the simultaneous bond reconstruction with detrapping. The efficiency of this process has been estimated to be less than 10-5.

Atomic migration of metallic atoms in the interfaces of Au-Si and Ni-Si is investigated with emphasis on the difference among c-Si, a-Si:H/c-Si and a-Si:F:H/c-Si. 40 MeV-O5+ ion backscattering spectra of the Au-Si system heat-treated at 350°C for 30 min indicate that Au atoms of more than 1020cm-3 were distributed in Si up to a depth of about 1 µm and 3 µm for a-Si:F:H/c-Si and a-Si:H/c-Si, respectively. Because the thickness of a-Si is about 5000 Å, this means that a large amount of Au migrated not only in the a-Si film but also into the substrate of c-Si even below the eutectic point, while Au-migration was not observed in the case of direct contact interface between Au and c-Si.

A simple method to produce an avalanche breakdown with a constant avalanche current in the silicon substrate of a MOS diode and to inject hot carriers into the gate oxide is presented. The shift of flatband voltage and that of the breakdown voltage of an n-type MOS diode are observed by hole injection into the gate oxide grown in dry oxygen using the above method. It is observed that about 1/10 of the injected holes could be captured by traps in the gate oxide. It is indicated by both the bias-temperature treatment and the avalanche injection process that hole traps would be generated by avalanche injected holes in the gate oxide. The trapped holes are located near the Si–SiO2 interface decaying from that interface.

Single domain GaAs layers were successfully grown on double domain Si(001) substrates by molecular beam epitaxy (MBE). During the growth, reflection high energy electron diffraction (RHEED) patterns of GaAs films grown on the Si substrates were monitored in situ. They changed gradually from initial spotty unreconstructed patterns to As stabilized (001)2×4 patterns. The morphologies of as grown surfaces and molten KOH etched surfaces of the films were observed by Nomarski optical microscope and also indicate that the films were single domain.

Results of research and development on DSA MOS transistors and their integrated circuits are reviewed. Characteristic features of the devices are listed. Examples of performance of the devices to be available in near future are proposed.

The two-dimensionality of the electronic system in a new self-aligned GaAs MIS-like FET having an n+-GaAs/undoped AlGaAs/undoped GaAs SIS structure is demonstrated by the angular dependent characteristics of SdH effects. The mobility of two-dimensional electron gas in a GaAs-SISFET is shown to be 120000 cm2/V·s with a sheet carrier concentration of 6.6×1011 cm-2 at 4.2 K and V G=0.6 V. The quantized Hall effect is realized by changing gate voltages at as low a magnetic field as 3.5 T.

We have measured the minority carrier (electron, in this case) lifetime in the laser recrystallized polysilicon on ceramics substrates by the open circuit voltage decay (OCVD) method and by the modulated photocurrent (MPC) method. We have found from both measurements that the lifetime in the Si film is comparable to or longer than 1 µs. We have discussed briefly the possible reasons for this rather long lifetime for recrystallized material.

The first integration of a GaAs FET-type device and a GaAs bipolar transistor-type device was achieved using the GaAs SISFET and GaAs inversion-base bipolar transistor (GaAs IBT). The GaAs SISFET showed the transconductance of g m=80 mS/mm and 190 mS/mm at 300 K and 77 K, respectively. The GaAs IBT showed the current gain of β=18 and 13 for the common emitter configuration at 300 K and 77 K, respectively.

In the GaAs inversion-baser bipolar transistor, the graded layer was introduced to the emitter barrier. It was proved that the graded layer decreased the effective barrier height of the emitter barrier and enhanced the electron flow from the emitter to the collector. These effects of the graded layer improved the current gain of the GaAs IBT by two orders of magnitude.

We have made Raman scattering studies on hydrogenated amorphous silicon (a-Si:H) prepared at high deposition rates ranging from 10–105 A/s. The full width of half maximum of the TO-like band, ΔωTO, increases with the increase in the deposition rate, r g, which implies an increase in the structural disorder of a-Si:H with the increase in r g. However, the degree of such increase is small when compared with those observed in a-Si:H alloy materials such as amorphous silicon carbide and amorphous silicon nitride. We have found that the value of ΔωTO is correlated with the B value (the square of the slope of √αh ν versus h ν plot).

Heteroepitaxial GaP films were grown on (100) oriented Si substrates by molecular beam epitaxy. During the growth, the substrates were irradiated with a Zn molecular beam. At growth temperatures lower than 450°C, a broad band luminescence due to Zn–O complexes was observed at room temperature.