This paper reports on an experimental evaluation of mechanical stress effects in SOI (Silicon on Insulator) power devices. In particular, this study focuses on the interaction of parasitic bipolar effects which are unique physical phenomenon of SOI-type devices. The electrical characteristics of SOI-power-nMOSFETs (power n-type Metal-Oxide-Semiconductor Field-effect-transistors) under mechanical loading are measured using a four-point bending method. It is demonstrated that the parasitic bipolar effects may accelerate the electrical variation induced by the mechanical stress effects. In addition, the experimental results show the following:

• There may be a load direction dependence in the drain conductance change under the parasitic bipolar region.

• Gate-length dependence is not clarified.

In this paper, we propose a design method for an artificial magnetic conductor (AMC) that considers the influence of the antenna substrate. Furthermore, we propose an antenna incorporating the AMC that can reduce the influence of the back environment. We have derived a formula to calculate the resonant frequency of the AMC considering the influence of the antenna substrate. As a result, the error from the analysis value is within 2.0%. It was also confirmed that the gain and front-back ratio were improved by incorporating the AMC into the antenna. In addition, the degradation of the reflection coefficient and antenna gain can be reduced even when there is a metal plate in the vicinity of the antenna, demonstrating the usefulness of the proposed antenna.

We examined the SPICE model of phase change materials (PCM) suitable for the coupled analysis of heat and electricity. When a PCM is modeled by a switch, the model becomes complicated and unsuitable due to calculation speed. On the other hand, modeling with a dependent current source enables fast calculation with a simple model, but there are unstable factors in the analysis. Therefore, a dependent current source model is desirable if stability can be ensured. In this report, using the SPICE model of PCM with a dependent current source, it was shown that by carrying out calculation at a time step of 1/100 or less of the PCM thermal time constant, it could be stably analyzed without increasing errors, and it could be used for the thermal analysis of a cooling system for electronic equipment.

For preliminary study of the practical application of direct bonding to semiconductor device chips, we coated Si chip surfaces with elastic resin thin films. Then, using atomic diffusion bonding processing, the chips were bonded with other substrates at room temperature. Using Si chips coated with 11-μm thick polyimide thin film, bonding defects caused by external particles were reduced remarkably. Moreover, we confirmed the reduction of bonding defects when bonding with a mirror-polished stainless-steel plate with large surface roughness of 3 nm. Results obtained for Si chips bonded with mirror-polished stainless steel revealed that polyimide thin film coating on Si chips is effective at suppressing defect formation at the bonded interface caused by differential thermal expansion of the Si chips and stainless steel.