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Epitaxial film transfer, a new technique for producing a single crystal Si film with both large size and high quality on an insulating substrate, is demonstrated. The technique in which an epitaxial Si film is transferred to a secondary substrate by using three fundamental processes of epitaxial growth, bonding of two wafers, and substrate elimination, can produce a 2-in. single crystal Si film as thin as 1.5 μm on a insulating substrate. Thickness variation can be controlled to ±0.06 μm across a 2-in. wafer. An epitaxial Si film is transferred without significant degradation in quality although a fine film waving exists.

A high-power and short-wavelength GaInP/AlGaInP quantum-well laser diode array was designed and fabricated. Because a conduction band offset of this material system is small, a carrier leakage from an active layer is an important limiting factor of the maximum light output. In this work, long cavity length of 1.5 mm, high front facet reflectivity of 18% and AlInP cladding layers were adopted to reduce the leakage. An evaluation test of the fabricated array was performed under CW operation. At 15°C, high light output of 12W was obtained with injection current of 16A. The lasing wavelength was 643.3 nm. Moreover, high wall-plug efficiency of 34% was achieved. These excellent characteristics are considered to be due to the effective suppression of the carrier leakage.

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This paper presents a silicon-micromachined microstrip antenna in which both feeding power and ground interconnection are performed along the vertical direction of the substrate at the wafer level. The antenna has a stacked structure consisting of a patch antenna substrate and a feed substrate. The structure possesses the following novel points: (i) it satisfies both optimum design and ease of wafer handling in the fabrication process; (ii) the ground plane intervened in the microstrip antenna is interconnected by through-wafer vias. The measured radiation patterns of the developed antenna at an 80-GHz band showed good agreement with the designed patterns. This newly developed technology can be utilized for wafer-level stacking to achieve a compact array antenna in the millimeterwave range.