Abstract: A static cross-coupled bipolar memory cell has a large read current/stand-by current ratio and short write time. The nonlinear load element includes a resistor with a parallel-connected pnp transistor serving as a diode and an inversely-operating npn transistor for dissipating charge carriers.

Abstract: An envelope for a photodiode which serves as a detector of light signals comprises a support and a metal cap-shaped member connected hermetically to the support. A metallized glass light conductor passed through an aperture of the cap-shaped member is connected in the aperture by means of solder. One end of the light conductor extends up to the photodiode; the other end projects from the cap-shaped member and is surrounded by the wall of an aperture on one side of a blocked-shaped member, in which aperture an optical fiber can be incorporated on the other side.

Abstract: A switchable analog signal inverter is suitable for inverting an input D.C. voltage, for example the D.C. voltage from a digital to analog converter (DAC), thereby halving the size of the DAC. The inverter includes a capacitor having one side alternately switchable between a reference voltage point and an output terminal and another side alternately switchable between the reference voltage point and an input signal terminal, and switching means for selectively reversing the phasing of the switching between the reference voltage and the input signal. In one embodiment the inverter comprises a double pole reversing switch having inputs connected to a signal input terminal and to a reference voltage point and a capacitor connected by a change-over switch to first and second outputs of the reversing switch and by another change-over switch to a signal output terminal or to the reference voltage point.

Abstract: A method of manufacturing a semiconductor device in which an aluminum-containing layer, hereinafter referred to as the aluminum source, is locally provided on a semiconductor body 1,2 of silicon and, in a subsequent diffusion treatment, aluminum is diffused from the aluminium source 3 into the silicon body 1,2, and an aluminum-doped region 4 is formed in the silicon body 1,2, characterized in that, prior to the diffusion treatment, the aluminum source 3 is divided into parts 5 each having an area which is small as compared with the area of the region 4 to be formed, with a mutual distance which is smaller than double the distance over which the aluminum in the diffusion treatment is diffused laterally into the silicon body 1,2, and which parts 5 have an uninterrupted shape and are so small that during the diffusion treatment their uninterrupted shape remains unvaried.

Abstract: An integrated circuit includes a number of diode-coupled gate circuits, each having an inverter transistor. The logic signals are coupled between the gate circuits by conductive tracks which also form the coupling diodes. These diodes are mono-poly or poly diodes, and are formed integrally with the conductive tracks to achieve a flexible yet simple construction.

Abstract: A method of manufacturing solar cells in a semiconductor wafer uses a first doped glassy layer which is spaced apart from the edges of the wafer, in combination with a second undoped glassy layer, so that, when the dopants are diffused from the first layer into the wafer, only that portion of the wafer beneath the first layer is doped. This simple and economical method results in solar cells having improved leakage characteristics.

Abstract: A semiconductor laser or traveling wave intensifier has an active layer between two passive semiconductor layers, and a strip-shaped electrode geometry. The active layer is uniform in thickness, while at least one of the passive layers within the strip-shaped geometry comprises a strip-shaped zone which contains portions having different refractive indices n.sub.1 and n.sub.2. According to the invention it holds that(n.sub.1 -n.sub.2) (d.sub.1 -d.sub.2)>0,wherein n.sub.1 is the refractive index of the portion which at least within said strip-shaped zone adjoins the active layer, d.sub.1 is the thickness thereof within the strip-shaped zone, and d.sub.2 is the thickness thereof beside the strip-shaped zone.

Abstract: A semiconductor laser includes an active layer of a first conductivity type comprising a strip-shaped active region formed by a doping of the second conductivity type over at least a part of the thickness of the active layer. According to the invention, the active region consists of a number of zones of the second conductivity type which are separated by material of the first conductivity type and which, viewed in the longitudinal direction of the active region, have a maximum dimension of at most 20 .mu.m. Upon ageing, crystal defects in the zones will not expand beyond the zones, thus extending the usable lifetime of the laser.

Abstract: A circuit arrangement for transmitting binary data elements `0` and `1` by frequency shift using two tone frequencies f0 and f1. The circuit arrangement comprises a modulator, an exclusive OR-gate and an integrator. A data signal DS produces from the modulator a digital signal DSS which by decoding of the integrator results in a tone signal TS comprising f0 or f1. The action of the OR-gate to which both signals DS and DSS are applied causes the amplitude of the tone signal TS to be substantially the same for each of the tone frequencies f0 and f1. The OR-gate may change either the effective resistive input into the integrator for each tone frequency or it may change the amplitude of the signal DSS for each tone frequency.

Abstract: A method of making a semiconductor device which includes at least one pair of complementary vertical bipolar transistors formed on a plate having a substrate formed of two adjacent portions of opposite conductivity type forming a p-n junction therebetween. The two adjacent portions form, respectively, the collector region of a first of the transistors and the emitter region of a second of the transistors. An electrode is provided on the lower face of the substrate to connect together the two adjacent portions of the substrate. The method of the invention is particularly applicable to making mixed Darlington amplifier structures and push-pull amplifiers composed of such structures.

Abstract: In an electronic clock circuit having both a stepper motor and a PXE (piezoelectric oxide) alarm element, the stepper motor and PXE element are connected in parallel and appropriate motor and PXE drive signals are provided on the same line. With this circuit configuration, an inductance and a transistor are eliminated from the prior art circuit, thus resulting in a smaller and less expensive device.

Abstract: A semiconductor device includes a first metallization pattern which is sunken into a portion of a first insulating layer on the semiconductor body. This first metallization pattern is sunken through only a part of the thickness of the first layer and its surface substantially coincides with that of the first layer. The first metallization pattern and first insulating layer are covered with a second insulating layer, and a second metallization pattern is provided on the second insulating layer. In order to provide contact with desired regions of the semiconductor device, the second metallization pattern extends through contact holes in the underlying second layer to provide the desired electrical connections. This configuration results in a flatter, more efficient and at the same time a more reliable multiple-layer metallization system.

Abstract: A semiconductor device such as an integrated Darlington circuit includes a mesa which is bounded by two parallel grooves which extend into the device substrate. A semiconductor resistor is formed in the mesa and extends from the mesa surface down to a buried epitaxial layer. This semiconductor resistor is separated from the grooves by a region of semiconductor material, so that its resistance may be established in an accurate and reproducible manner.

Abstract: A semiconductor laser/amplifier is disclosed in which the radiation oscillates only in one longitudinal mode. According to the invention this is achieved by a strip-shaped active region which exhibits periodic variations in amplification (and preferably also in the amplification profile) in its longitudinal direction over at least a part of its length. The period of the amplification variation is at least ten times the wavelength of the radiation.

Abstract: A digital signal transmission system in which a pulse code modulated (PCM) signal is retimed in a regenerator using a decision circuit supplied by a clock, the frequency of which is half that of the bit rate (typically 1 Gigabit/second), and is demultiplexed using multiplexers clocked at a frequency half that of the bit rate. In each case the clock frequency is derived from the data stream using a clock extractor. A voltage controlled oscillator (VCO) generating a signal at substantially half the bit rate is connected to one input of a phase detector to another input of which is connected to receive current pulses representing transitions in the incoming data signal. The phase detector comprises first, second and third pairs of long tailed-pair connected transistors, the collectors of the transistors of the first pair of being connected respectively to the common connected transistors of second and third pairs.

Abstract: A semiconductor laser device includes a support having a substantially annular assembly block of a metal having a good thermal conductivity, which assembly block includes positioning means on its outer circumference for accurately locating the optical axis of said laser element and a sector-shaped supporting part which extends towards the center line of the block and which has a connection and mounting face for a laser element extending through the center line and accurately located with respect to the positioning means. A base includes mutually-insulated electrical conductors and a photodiode which is secured on the side of the assembly block remote from the supporting part, and a cap having a light-transmitting window is secured to the assembly block so as to form a hermetic envelope.

Abstract: Compensation for an effect produced by variations in the base-widths of integrated circuit transistors occurring from batch to batch is obtained by including in each integrated circuit a resistor the resistance of which has an inverse relationship to the transistor base widths and generating a phase shift in the signal path through the transistors, which phase shift depends on the value of the resistance in such manner that a relative phase advance is obtained with increasing values of the base widths. A control signal which depends on the value of a "base-under-emitter" resistor is produced at the output of a control signal generator circuit and is applied to an n-type island in which a "shallow-p" resistor is formed, thereby controlling the reverse bias of the island-resistor junction and hence the capacitance between the resistor and ground.

Abstract: A method of manufacturing cooling blocks for semiconductor lasers, in which the rounding-off radius of the line of intersection between two surfaces of the cooling blocks must have a very small value. In the method, two bodies to be formed into cooling blocks are each provided with a flat surface and these bodies are secured together with their flat surfaces by means of a curable adhesive. One side of the bodies connected together is subjected, transverse to the two surfaces connected together, to a machining treatment so as to obtain a further flat surface, in which machining treatment deformation and burring of the bodies near the line of intersection to be formed is avoided due to the presence of the cured adhesive, and a line of intersection having a rounding-off radius of only a few microns is formed.

Abstract: A method of manufacturing an IGFET device in an entirely self-registering manner, in which on the semi-conductor body a narrow silicon nitride strip is formed which covers only the active region of the body and the width of which is substantially equal to that of the transistors to be manufactured and possibly other circuit elements. This nitride strip is used as a mask for providing the channel stopper zone and as an oxidation mask for providing a first oxide layer. The nitride strip is then etched in which the strip is locally removed over its entire width and only parts remain above the channel region and contact regions which form a second oxidation mask and, in cooperation with the first oxide layer, a doping mask. The source and drain zones of the transistors and possibly further zones, for example underpasses, are formed via said doping mask after which by oxidation a sunken oxide pattern is formed over the whole surface with the exception of the channel regions and the contact regions.

Abstract: An electroluminescent semiconductor device such as a semiconductor laser has epitaxial monocrystalline layers (3 to 6), including an active layer (4), grown on a substrate (2). The epitaxial layers are etched in the presence of an etching mask (8) to form nonplanar mirror surfaces (9) which in the longitudinal direction bound active regions (10). To form flat and parallel mirrors (12) an epitaxial monocrystalline protective layer (11) is grown from the gaseous phase on the mirror surfaces after etching. The etching can be carried out in two stages using different etchants. With the first etchant the etched layers taken on a swallow-tail profile and then with the second etchant they take on a concave profile.