Abstract: A switch with an actuator has two supporting columns on a substrate, and a rocking plate on the supporting columns. The rocking plate is pivoted by (pivotally mounted on) the two supporting columns. The rocking plate is made of conductive material, so that it can be subjected to electrostatic force of an adsorption electrode. In the switch, it is not necessary to provide a narrow beam to support the rocking plate, because the rocking plate is pivoted by the supporting columns. Therefore, the switch is a long-life microswitch.

Abstract: The present switch including the present actuator has a supporting column on a substrate, and a cap plate provided on the supporting column. The supporting column pivotally supports the cap plate. At ends of the cap plate, a plurality of beams are provided, respectively. The plurality of beams are subjected to electrostatic force of absorbing electrodes. According to the present switch, tilting directions of the cap plate (beams) can be set freely. Therefore, by providing the beams in a plurality of directions desired by a user and positioning the absorbing electrodes on the substrate so that the absorbing electrodes respectively correspond to the beams, the cap plate can be tilted in a plurality of desired directions. With this arrangement, the present switch has high degree of freedom as to the positions and number of substrate contact points.

Abstract: An amplifier GaAs MMIC for microwave band applications includes a ground electrode 8 having a via hole group 12 composed of three via holes 11 filled with plated metals 10a that are formed adjacently. The interaction thereby generates high frequency electromagnetic bonding, which reduces the ground inductance. According to the MMIC, the ground inductance of the via hole may be reduced while decrease of a strength and increase of a size being restrained.

Abstract: A switch with an actuator has two supporting columns on a substrate, and a rocking plate on the supporting columns. The rocking plate is pivoted by (pivotally mounted on) the two supporting columns. The rocking plate is made of conductive material, so that it can be subjected to electrostatic force of an adsorption electrode. In the switch, it is not necessary to provide a narrow beam to support the rocking plate, because the rocking plate is pivoted by the supporting columns. Therefore, the switch is a long-life microswitch.

Abstract: In a semiconductor apparatus, a plurality of HBTs (heterojunction bipolar transistors) are formed on a front surface consisting of a (100) crystal plane of a GaAs substrate. Via holes passing thorough the GaAs substrate are formed in proximity of the HBTs. Each via hole has a rectangular-shaped hole edge at the front surface side of the GaAs substrate. The longitudinal direction of the hole edge on the surface side of the via hole is parallel to the [011] direction of crystal orientation of the GaAs substrate. A width of the via hole in a direction perpendicular to the [011] direction of crystal orientation is larger at the back surface of the substrate than at the front surface thereof.

Abstract: A heterojunction bipolar transistor is fabricated by laminating and emitter layer, a base layer and a collector layer on a top surface of a semiconductor substrate, forming a via hole through the emitter layer, the base layer, the collector layer and the substrate at a specific depth, and providing a heat sink layer made of a metal on a rear surface of the substrate. A surface electrode of the emitter layer and the heat sink layer are connected to each other by a metal wiring line running through within the via hole, thereby improving the heat radiation and reducing the emitter inductance.

Abstract: The present switch including the present actuator has a supporting column on a substrate, and a cap plate provided on the supporting column. The supporting column pivotally supports the cap plate. At ends of the cap plate, a plurality of beams are provided, respectively. The plurality of beams are subjected to electrostatic force of absorbing electrodes. According to the present switch, tilting directions of the cap plate (beams) can be set freely. Therefore, by providing the beams in a plurality of directions desired by a user and positioning the absorbing electrodes on the substrate so that the absorbing electrodes respectively correspond to the beams, the cap plate can be tilted in a plurality of desired directions. With this arrangement, the present switch has high degree of freedom as to the positions and number of substrate contact points.

Abstract: A heterojunction bipolar transistor includes an emitter layer, a base layer and a collector layer laminated on a top surface of a semiconductor substrate, and a heat sink layer made of a metal and provided on a rear surface of the substrate. A via hole is cut through the emitter layer, the base layer, the collector layer and the substrate. A surface electrode of the emitter layer and the heat sink layer are connected to each other by a metal wiring line running through within the via hole, which is capable of improving the heat radiation and reducing the emitter inductance.

Abstract: A heterojunction bipolar transistor includes an emitter layer, a base layer and a collector layer laminated on a top surface of a semiconductor substrate, and a heat sink layer made of a metal and provided on a rear surface of the substrate. A via hole is cut through the emitter layer, the base layer, the collector layer and the substrate. A surface electrode of the emitter layer and the heat sink layer are connected to each other by a metal wiring line running through within the via hole, which is capable of improving the heat radiation and reducing the emitter inductance.

Abstract: An amplifier GaAs MMIC for microwave band applications includes a ground electrode 8 having a via hole group 12 composed of three via holes 11 filled with plated metals 10a that are formed adjacently. The interaction thereby generates high frequency electromagnetic bonding, which reduces the ground inductance. According to the MMIC, the ground inductance of the via hole may be reduced while decrease of a strength and increase of a size being restrained.

Abstract: In a semiconductor apparatus, a plurality of HBTs (heterojunction bipolar transistors) are formed on a front surface consisting of a (100) crystal plane of a GaAs substrate. Via holes passing thorough the GaAs substrate are formed in proximity of the HBTs. Each via hole has a rectangular-shaped hole edge at the front surface side of the GaAs substrate. The longitudinal direction of the hole edge on the surface side of the via hole is parallel to the [011] direction of crystal orientation of the GaAs substrate. A width of the via hole in a direction perpendicular to the [011] direction of crystal orientation is larger at the back surface of the substrate than at the front surface thereof.

Abstract: The amplifier semiconductor element of this invention includes a field effect transistor of which a threshold voltage V.sub.th has a predetermined relationship with an operating voltage.