Abstract: A semiconductor physical quantity sensor, in which a beam-structure having a movable electrode and a fixed electrode confronted with the movable electrode are integrally formed in one substrate, having a new electric isolation structure. A semiconductor physical quantity sensor such as an acceleration sensor includes a silicon substrate; a laterally extending hollow formed in the silicon substrate; and a base plate portion defined below the hollow in the silicon substrate. A rectangular frame portion, a beam-structure having a movable electrode, and a fixed electrode is defined by the hollow and trenches. The fixed electrode confronts with the movable electrodes of the beam-structure. Trenches, in which electrical insulating material is buried, are formed between the movable electrode and the rectangular frame portion and between the fixed electrodes and the rectangular frame portion.

Abstract: An angular velocity sensor device includes drive oscillators oscillated by driving in drive direction a0, and detecting oscillators connected to the drive oscillators and oscillated in detecting directions a1, a2 by a Coriolis force, which is generated by an angular velocity in a direction K. The directions a1, a2 respectively make an angle &thgr; with the direction K. Detection electrodes are provided for the detecting oscillators, and produce output signals. A signal caused by an inertia force and a signal caused by the Coriolis force are obtained from the output signals, and the angular velocity is determined by the two signals.

Abstract: A compact angular velocity sensor, which can improve an S/N (signal/noise) ratio. An angular velocity sensor includes an SOI substrate, four oscillatory masses movably supported to the SOI substrate, and four detection electrodes provided outer side of the oscillatory masses for detecting displacements of the oscillatory masses. The oscillatory masses are arranged point-symmetry with respect to a predetermined point K in a flat plane parallel to the SOI substrate. Each of the four oscillatory masses adjacent each other is oscillated in reverse phase in a circumstantial direction about the predetermined point K along the flat plane. When an angular velocity &OHgr; is generated about the predetermined point K, detection weights of the oscillatory masses are displaced along a direction perpendicular to oscillation direction in the flat plane.

Abstract: A method of manufacturing a semiconductor device, which can effectively form a trench having a high aspect ratio with relatively simple steps. An initial trench is formed in a silicon substrate by a reactive ion etching using an oxide film mask as an etching mask. After forming a protection oxide film on an inside surface of the trench, a part of the protection oxide film at which positions at a bottom surface of the trench is removed by a reactive ion etching, so that an etching of the silicon substrate is advanced through the bottom surface of the trench. Furthermore, the step for forming the protection oxide film and the step for re-etching the bottom surface of the trench are repeatedly performed, so that a depth of the trench becomes a predetermined depth. These steps are performed in a common chamber by using plasma processed with switching gases to be introduced to the chamber.

Abstract: A semiconductor device comprising: a semiconductor substrate; a diffused region extending from the surface and to the inside of the semiconductor substrate; a first insulating layer formed on the semiconductor substrate and having a contact hole located through which the diffused region is exposed; a first conductor layer formed on a portion of the first insulating layer and connected so the diffused region through the first contact hole; and an insulator section made of an oxide of the substance of the first conductor layer and formed on another portion of the first insulating layer to surround the first conductor layer.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency waves intruding into electronic circuits. The high frequency wave absorbing ceramics are composed of a ternary composition comprising from 55 to 85 mol % of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, from 10 to 40 mol % of lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and not more than 20 mol % of lead nickel tantalate Pb(Ni.sub.1/3 Ta.sub.2/3)O.sub.3 based on the total 100 mol % of a composition composed of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and lead nickel tantalate Pb(Ni.sub.1/3 Ta.sub.2/3)O.sub.3.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency waves intruding into electronic circuits. The high frequency wave absorbing ceramics are composed of a ternary composition comprising from 50 to 80 mol % of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, from 10 to 40 mol % of lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and not more than 40 mol % of lead iron tantalate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3 based on the total 100 mol % of a composition composed of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, lead iron tungstate Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and lead iron tantalate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency wave intruding into electronic circuits. The high frequency wave absorbing ceramics are composed of a ternary composition comprising from 50 to 82.5 mol % of lead iron niobate Pb(Fe1/2Nb1/2)O.sub.3, from 17.5 to 40 mol % of lead iron tungstate Pb(Fe2/3W1/3)O.sub.3 and not more than 25 mole % of lead cobalt niobate Pb(Co1/3Nb2/3)O.sub.3 based on the total 100 mol % of a composition composed of lead iron niobate Pb(Fe1/2Nb1/2)O.sub.3, lead iron tungstate Pb(Fe2/3W1/3)O.sub.3 and lead cobalt niobate Pb(Co1/3Nb2/3)O.sub.3.

Abstract: A high frequency filter assembly for an electric instrument including an internal electric circuit element arranged within a casing of metallic conductive material, and a connector mounted on a peripheral wall of the casing for connecting an external electric circuit to the internal electric circuit element. The filter assembly comprises at least a pair of overlapped insulation thin plates to be arranged between the connector and a connection terminal of the circuit element, and an earth electrode strip disposed between the insulation thin plates and being connected to a portion of the casing.

Abstract: A high frequency wave absorbing ceramics can be used, for example, as an EMI preventive filter for interrupting high frequency waves intruding into electronic circuits. The high frequency wave absorbing ceramics has a composition expressed by the chemical formula Pb{Fe.sub.1/2 Nb.sub.(1/2-x) Ta.sub.x }O.sub.3 where 0.1<x<0.35. The high frequency wave absorbing ceramics may be composed of a composition comprising from 30 to 80 mol % of lead iron niobate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3 based on the total 100 mol % of a Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 and from 20 to 70 mol % of lead iron tantalate composition composed of lead iron niobate Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 and lead iron tantalate Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3.