Abstract: When a variable capacitance diode device is formed on each of chips obtained by cutting off a wafer, the capacitance values of the diode devices formed on the chips disperse for each wafer due to change in the manufacturing process conditions. To reduced the dispersion in capacitance value of the diode devices, a plurality of variable capacitance diodes (10A, 10B and 10C) are formed on the same semiconductor chip (2) in such a way that the areas of the PN junctions (4A, 4B and 4C) of the respective diodes are different from each other. Further, only one variable capacitance diode (e.g., 10C) which can satisfy a predetermined strict standard is selected and connected to a terminal (11) for use.

Abstract: There is provided a variable capacitance diode device. The device comprises a semiconductor substrate of a first conductive type, an epitaxial layer of the first conductive type with a high specific resistance formed on the semiconductor substrate, a first diffusion layer of the first conductive type, in which impurities are more diffused than the epitaxial layer, formed in the epitaxial layer and a second diffusion layer of a second conductive type which forms a junction with the first diffusion layer. The first diffusion layer is formed in a hollow cylindrical body or a hollow square pole body, etc., so as to enlarge an outer peripheral area thereof.

Abstract: An semiconductor junction capacitance element equipped with the function of preventing electrostatic breakdown is disclosed in which a main PN junction adapted to serve as variable capacitance diode is defined in an epitaxial layer of a first conductivity type. A diffusion layer of the first conductivity type is provided in the epitaxial layer at a position spaced apart from a lateral PN junction which is exposed at major surface of the epitaxial layer so that the breakdown voltage of the lateral PN junction is set up to be lower than the breakdown voltage of the main PN junction by virtue of the provision of the diffusion layer.

Abstract: A plurality of variable-capacitance diode elements are formed in the top of a semiconductor substrate. The rear surface of the substrate is connected to a first lead frame that acts as a common electrode for one electrode from each of the variable-capacitance diode elements. Each of the other electrodes of the variable-capacitance diode elements is connected by a wire to a second lead frame. In this manner, a single variable-capacitance diode device is formed between the first and second lead frames by a plurality of variable-capacitance diode elements.

Abstract: A work holding apparatus is a work holder for holding a work in a predetermined position in relation to a basic member. A base column is rotatably supported astride on two sets of base plates. Holding fixtures are removably mounted on each side of the base column, such that different types of works can be supported and clamped by the holding fixtures. An indexing-rotation driving device rotates the base column such that it may be applicable to various types of works, thereby facilitating the holding of many types of works and the replacement of supporters and clamps. Furthermore, the base plate for supporting the base column is divided into two sets to reduce the weight of the base plate moving parts, and a base plate synchronizing means is provided to insure synchronized operation of the two base plates.

Abstract: A process for the preparation of a dibromopropyl ether compound having a high melting point, which comprises mixing a bis-dibromopropyl ether of tetrabromobisphenol-sulfone or tetrabromobisphenolpropane represented by the following general formula: ##STR1## in the melted state with a crystallized product of said compound at a temperature lower than the melting point of the crystallized product, and holding the mixture at a temperature of 50.degree. to 100.degree. C.According to this process, the dibromopropyl ether compound of a high melting point can be prepared without using an organic solvent.

Abstract: A variable-capacitance diode element is disclosed which comprises a semiconductor substrate of a first conductivity type having an epitaxial layer of the first conductivity type provided on a main surface portion thereof, said epitaxial layer having a higher resistivity than that of said semiconductor substrate; a first diffusion layer of the first conductivity type diffused in said epitaxial layer and having a lower resistivity than that of said epitaxial layer; a second diffusion layer of a second conductivity type surrounded by said first diffusion layer and having a lower resistivity than that of said first diffusion layer; and a third diffusion layer of the second conductivity type of a small diffusion length covering an exposed portion of a major surface of said first diffusion layer and an exposed portion of a major surface of said second diffusion layer. With such construction, the capacitance variation range of the diode element is widened, and the high-frequency serial resistance R.sub.

Abstract: A variable-capacitance diode element is disclosed which comprises a semiconductor substrate of a first conductivity type having an epitaxial layer of the first conductvity type provided on a main surface portion thereof, said epitaxial layer having a higher resistivity than that of said semiconductor substrate; a first diffusion layer of the first conductivity type diffused in said epitaxial layer and having a lower resistivity than that of said epitaxial layer; a second diffusion layer of a second conductivity type surrounded by said first diffusion layer and having a lower resistivity than that of said first diffusion layer; and a third diffusion layer of the second conductivity type of a small diffusion length covering an exposed portion of a major surface of said first diffusion layer and an exposed portion of a major surface of said diffusion layer. With such construction, the capacitance variation range of the diode element is widened, and the high-frequency serial resistance R.sub.

Abstract: A variable-capacitance diode element having a wide capacitance variation range is disclosed which comprises an epitaxial layer of a first conductivity type which is provided on a semiconductor substrate of the first conductivity type; a diffusion layer of the first conductivity type which is formed in the epitaxial layer with a higher concentration than said epitaxial layer by means of ion implantation; at least one diffusion layer of a second conductivity type which is formed in the diffusion layer of the first conductivity type so as to define PN junction; and a first-conductivity type buried layer of a low resistivity which is formed the boundary portion between the semiconductor substrate and the epitaxial layer where a depletion layer reaches which occurs in response to a reverse bias voltage being applied to the PN junction, whereby the depletion layer is caused to extend to a maximum possible effect.

Abstract: In a variable-capacitance diode device consisting of a PN junction, and a semiconductor layer of a first conductivity type, the impurity concentration of which decreases as the depth from the PN junction increases, the semiconductor layer of the first conductivity type is arranged to include, except in the vicinity of the PN junction, at least one such point that the following relationship holds true:Ai.ltoreq.Ai+1 (i=1, 2, . . . , n)where Ai represents impurity concentration of said semiconductor layer of the first conductivity type at a distance Xi as viewed depth-wise of the PN junction.

Abstract: A semiconductor device characterized in that at least two elements having approximately the same area are formed on the same chip, the two elements are so disposed as to be sectionalized by a street, having an angle with respect to any scribe lines along which the semiconductor device is to be cut, and the semiconductor device is composed of a pattern adapted for easy pattern recognition by detecting the street.

Abstract: A method of making a variable-capacitance diode device including semiconductor layer a first conductivity type in which the impurity concentration decreases with increasing depth from surface of a PN junction. The semiconductor layer of the first conductivity type is formed by diffusing an impurity element of the first conductivity type in a semiconductor substrate with a high degree of concentration. Thereafter, a semiconductor layer of a second conductivity type is formed which has such an impurity concentration profile that the concentration of impurity element of the second conductivity type is lower than the impurity concentration of said semiconductor layer of the first conductivity type formed in said semiconductor substrate and at a predetermined depth, the concentration of the second conductivity type impurity element is substantially equal or close to the concentration of the first conductivity type impurity element.

Abstract: Bis-(4-hydroxy-3,5-dibromophenyl) sulfone is converted to an allyl ether in the presence of an alkali with allyl chloride in the presence of a bromide and/or an iodide, and/or a substance capable of forming a bromide and/or an iodide by reaction with the alkali.

Abstract: A flame retardant for polyolefins, which comprises as an effective ingredient a hardly water-soluble or water-insoluble, nitrogen-containing phosphorus compound obtained by mixing 100 parts by weight of a condensed phosphoric acid compound with 10 to 100 parts by weight of a triazine compound and heating the mixture at 100.degree. to 250.degree. C. in the presence or absence of water.

Abstract: Highly durable flame-retardant thermoplastic polymer compositions contain thermoplastic polymer consisting of an ethylenically unsaturated monomer and from 0.1 to 20%, based on the weight of the thermoplastic polymer, of specific brominated alkoxydiphenyl sulfone derivative of the formula: ##STR1## WHEREIN A is a member selected from the group consisting of a hydrogen atom and allyl, propyl and 2,3-dihalogenopropyl groups, and X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are members selected from the group consisting of chlorine and bromine atoms with at least two of them being bromine atoms.

Abstract: Highly durable flame-retardant polyurethanes can be produced by the process wherein 3 mols of dibromoneopentyl glycol is reacted with 0.5 to 4 mols of phosphoric anhydride, the ester thus obtained is reacted with at least one member selected from the group consisting of alkylene oxides and haloalkylene oxides and then, the phosphorus compound thus obtained, as a portion of a polyhydroxyl component, is incorporated with another polyhydroxyl compound and reacted with a polyisocyanate component in the presence of a catalyst.