Abstract: A method for operating a magnetic logic device (10) is described wherein at least one output variable O=F (IA, IB) is formed from input variables (IA, IB) by at least one logic operation with an operator function F of the magnetic logic device (10), whereby the logic device (10) is set at a starting state for executing the operator function F with a certain operator control signal (SET) before the operation, whereby the operator control signal is selected from a group of control signals with which various non-volatile starting states can be set in a controlled manner, each state being characteristic of a different logic function. Furthermore, a magnetic logic device (10) equipped for implementation of this method is also described.

Abstract: A method of fabricating a compositional semiconductor device comprising a antum well wire or quantum dot superlattice structure, in particular a device selected from the group comprising lasers, photodiodes, resonant tunneling transistors, resonant tunneling diodes, far infrared detectors, far infrared emitters, high electron mobility transistors, solar cells, optical modulators, optically bistable devices and bipolar transistors, by epitaxial growth of the superlattice structure on a semiconductor substrate, is characterised in that the epitaxial growth is effected on a {311}, {211}, {111} or {110} substrate, and that the devices preferably have length and width dimensions less than 500 .ANG. and especially less than 300 .ANG..

Abstract: A unipolar electronic component is proposed with a quasi one dimensional carrier channel which has all the characteristics of an FET. This component can be very simply produced, has "self-alignment" and linear gates with a low capacity in place of planar gates. In this way a very high operating frequency of the component is possible. The structure comprises an initially homogenous 2D-layer with a high carrier mobility which is formed by epitaxy of for example GaAs. The implantation of focussed ions (for example Ga.sup.+ with 100 keV) locally destroys the conductivity of the electron layer. The irradiated regions remain insulating at low temperature or room temperature even after illuminating the cristal with bandgap radiation. The writing in of the insulating layer is carried out along two paths on the chip so that the 2D-carrier layer is subdivided into three regions insulated from one another.

Abstract: A novel unipolar transistor device has been realized starting from two-dimensional electron systems (2DES) in modulation-doped AlGaAS/GaAs heterostructures. A 600 nm wide 1D channel is insulated laterally from 2DES regimes by 700 nm wide deep mesa etched trenches. The conductivity in the quasi-one-dimensional channel can be tuned via the in-plane lateral-field effect of the adjacent 2DES-gates where the vacuum (or air) in the etched trenches serves as the dielectric. Room temperature operation is demonstrated yielding a 161S transconductance corresponding to 160 mS/mm 2D transconductance.

Abstract: A semiconductor device consisting of epitaxial material is provided with at least one monoatomic layer of doping atoms, i.e. with a layer which is just one atom thick. A preferred device is a bipolar transistor in which case the Dirac-delta doped p-type layer 38 is directly between n-type collector and emitter layers (32, 33). The bipolar transistor described herein has an extremely low base width and is capable of operating at high frequencies.

Abstract: A unipolar electronic component is proposed with a quasi one dimensional carrier channel which has all the characteristics of an FET. This component can be very simply produced, has "self-alignment" and linear gates with a low capacity in place of planar gates. In this way a very high operating frequency of the component is possible. The structure comprises an initially homogenous 2D-layer with a high carrier mobility which is formed by epitaxy of for example GaAs. The implantation of focussed ions (for example Ga.sup.+ with 100 keV) locally destroys the conductivity of the electron layer. The irradiated regions remain insulating at low temperature or room temperature even after illuminating the cristal with bandgap radiation. The writing in of the insulating layer is carried out along two paths on the chip so that the 2D-carrier layer is subdivided into three regions insulated from one another.

Abstract: A semiconductor light wave detector which has a first layer of a highly doped n-type semiconducting substrate, a second layer of a highly doped n-type semiconducting material, a third layer of a distinct intrinsic semiconducting material and a fourth layer of a highly doped n-type semiconducting material similar to the second layer. First and second electrical connections are provided to the fourth layer and to at least one of the first and second layers. A plurality of pairs of Dirac-delta doped monoatomic layers are in the third layer, with the first monoatomic layer of each pair being a layer of donors and with the second monoatomic layer of each pair being acceptors spaced from the donor layer and positioned on the side thereof facing the fourth layer.

Abstract: An optically bistable semiconductor device which has a doped or undoped gallium arsenide substrate and a series of alternating n-type and p-type Dirac-delta doped monoatomic layers formed on the substrate. Each Dirac-delta doped monoatomic layer is separated from the next adjacent Dirac-delta doped monoatomic layer by a layer of pure, undoped intrinsic semiconductor material such as gallium arsenide.

Abstract: An electron-wave coupled semiconductor device, in particular a semiconductor switching device, comprises a first layer of semiconducting material having a first bandgap, and a second layer of material formed on said first semiconducting layer and having a second bandgap greater than the first said bandgap. First and second electron waveguides are formed alongside but spaced apart from each other in the first semiconductor layer adjacent the boundary between this layer and said second layer. A gate region extends over said second layer transverse to and over said electron waveguides. First contact means provides input connections to said first and second electron waveguides on one side of said gate region and further contact means provides separate output connections from said first and second electron waveguides on the opposite side of the gate region from said first contact means.

Abstract: A semiconductor device consisting of epitaxial material is provided with at least one monoatomic layer of doping atoms, i.e. with a layer which is just one atom thick. A particularly preferred device is injection laser in which case the Dirac-delta doped layers 45 and 46 are within intrinsic layer 43. The injection laser is constructed with a hetero structure.

Abstract: A multiple quantum well light emitting compositional semiconductor device ch as a laser diode or a light emitting diode has an active region comprising an alternating sequence of layers of well layer material and of barrier layer material. The thickness of the barrier layer and of the adjacent well layers is chosen such that for one type of charge carrier a relatively high probability exists for such charge carriers to be present in the barrier region whereas the other type of charge carriers are localized in the potential wells. In this way it is possible to reduce the probability of non-radiative Auger recombination processes occurring thus reducing the threshold current and increasing the quantum efficiency of the device.

Abstract: A semiconductor device consisting of epitaxial material is provided with at least one monoatomic layer of doping atoms, i.e. with a layer which is just one atom thick. A particularly preferred device is a field effect transistor in which case the Dirac-delta doped layer 13 extends between the source and drain zones (18, 19) respectively. The field effect transistor can be constructed either with a homogeneous structure or with a hetero structure or with a superlattice structure. The field effect transistors described herein have a high transconductance and are capable of operating at high current densities.

Abstract: A semiconductor device of the doping superlattice type for detecting electromagnetic radiation or particles comprises a semi-insulating substrate (10), a first layer (11) of either n-type or p-type conductivity deposited thereon, a plurality of layers (12, 13, 14) of alternating conductivity types deposited in series on said first layer (11), a strongly p-type electrode region which extends through said p-type and n-type layers (11, 12, 13, 14) and defines a first selective electrode (15), and a strongly n-type electrode region which also extends through said p-type and n-type layers (11, 12, 13, 14), and which is spaced apart from said strongly p-type region and defines a second selective electrode. The device is a homogeneous semiconductor in which the n-type and p-type layers other than the first layer (11) and the outermost layer (14)have substantially identical thicknesses and doping concentrations.

Abstract: A heterostructure semiconductor device as a Schottky gate field-effect tristor comprises a semiconductor body including first and second layers made of different semiconductor materials, as gallium arsenide and aluminium gallium arsenide. A narrow heterojunction is formed between the layers. The material of the first layer is pure and comprises a minimum of defects. The second layer comprises a doping material, the concentration of which being at least one order of magnitude higher than the concentration of any doping or impurity material present in the first layer. The semiconductor and doping materials are chosen such that the energy levels occupied by the shallow doping material atoms in said second layer have an energetically more unfavorable position than an adjacent of the energy bands of the first layer so that free charge carriers from the doped second layer can migrate in an adjacent region of the first layer.

Abstract: A semiconductor laser device comprises a plurality of layers of semicondung materials, first contact means providing electrical contact to a basal layer of the device and second contact means providing electrical contact to an upper layer of the device, with at least one layer disposed between the basal layer and the upper layer being selected to be sufficiently thin that size quantization occurs, i.e. that a semiconductor device with a quantum well structure is created. The second contact means comprises a first strip-like contact overlying a first lasing region of the device and a second strip-like contact overlying a second lasing region of the device. The light losses associated with photons generated by laser action in the first region are intentionally made different from the light losses associated with photons generated by laser action in the second region which permits laser action at two distinct wavelengths in a monolithic device.

Abstract: A new method for GaAs substrate preparation which significantly reduces the ormation of oval defects during MBE growth of selectively doped n-Al.sub.x Ga.sub.1-x As/GaAs heterostructures. The method simply requires treatment in H.sub.2 SO.sub.4 after mechano-chemical polishing in NaOCl solution and generation of a protective surface oxide during in soldering. Routinely a density of oval defects of less than 200 cm.sup.-2 is achieved for 2-.mu.m thick heterostructures. The efficiency of the new preparation procedure is demonstrated by 2DEG mobilities in excess of 10.sup.6 cm.sup.2 /Vs at 6K obtained with a spacer width as narrow as 18 nm.