A production method (fig.2) of an IPG transistor (fig.1, 101) comprises: producing a channel portion (4) in which a quasi-one-dimensional conductive channel (6) electrically connecting between a source region and a drain region is generated, on a substrate (1); and producing gate portions (5a, 5b), each portion including a gate electrode layer (21a, 21b) for controlling generation and forfeiture of the quasi-one-dimensional conductive channel (6) so that upper surface of the gate layer (21a, 21b) and the quasi-one-dimensional conductive channel (6) are positioned substantially on the same plane, at both sides of the channel portion (4) on the substrate (1). At producing the gate portions (5a, 5b), gaps (13a, 13b) between the channel portion (4) and the gate portions (5a, 5b) are regulated by side walls (12a, 12b) produced self-aligningly on the side wall surfaces of the channel portion (4). Thus, the gap grooves (13a, 13b) of a high aspect ratio can be produced between the channel portion (4) and the gate portions (5a, 5b) without being restricted by the dry etching technique.

A structure for use in a magnetic recording and/or readback head comprises at least first and second layers of silicon-aluminium-iron (SiAlFe), known as sendust. In one embodiment the multilayered magnetic structure (50) includes a seed layer (53) of a first sendust alloy and a bulk layer (55) of a second sendust alloy overlying the seed layer, providing greatly improved anisotropic field and soft magnetic characteristics for the structure over a relatively wide range of compositions for the sendust material used for the bulk layer. The seed layer can be a single sendust layer or, alternatively, can be a multilayered structure (63) including layers of a gas-doped sendust material (67) and layers of non-doped sendust material (69) formed in an alternating sequence. The dopant gas is a gas such as nitrogen, oxygen or air, for example. Because of the hardness exhibited by sendust films, the described multilayered sendust films are excellent candidates for magnetic shields and inductive pole tips exposed at the air bearing surface of a transducer in a magnetic storage device.

A solid state, electronic, optical transition device includes a multiple-layer structure of semiconductor material which supports substantially ballistic electron/hole transport at energies above/below the conduction/valance band edge. The multiple layer structure of semiconductor material includes a Fabry-Perot filter element for admitting electrons/holes at a first quasibound energy level above/below the conduction/valance band edge, and for depleting electrons/holes at a second quasibound energy level which is lower/higher than the first energy level. Such an arrangement allows common semiconductor material to be used to produce emitters and detectors and other devices which can operate at any of selected frequencies over a wide range of frequencies.

A device for converting a set of electronic signals that represent an image into a coherent image includes a two-dimensional array of asymmetric Fabry-Perot (ASFP), quantum-well-based optical modulators connected on a pixel-by-pixel basis to a two-dimensional array of drive circuits located on an integrated circuit. Electronic signals received by the integrated circuit cause the pixel drive circuits to change a bias voltage applied across the optical modulator section and, thereby, change the optical properties of the optical modulator section of the device. The two-dimensional array can be used to impart intensity-only, phase-only, or phase-and-intensity variations onto a beam of coherent laser light incident on the array. This coherent image can be used with other optical elements to form optical processing machines and optical storage devices.

A method for manufacturing a nonlinear, dual-axis thin-film magnetic device which can be used as an electronic article surveillance system marker. The method includes providing a substrate having a surface characterized by first and second generally perpendicular axes. A magnetic field oriented parallel to the first axis is applied on the surface of the substrate. A first stack of relatively thin thin-film magnetic layers separated by nonmagnetic thin-film layers is grown on the substrate. The relatively thin thin-tim layers are grown in the presence of the magnetic field to a thickness sufficiently thick that the layers exhibit magnetic properties that are substantially independent of surface effects, but sufficiently thin that the easy axis of magnetization is oriented parallel to the second axis. A second stack of relatively thick thin-film magnetic layers separated by nonmagnetic thin-film layers is grown on the first stack. The relatively thick thin-film layers are grown in the presence of the magnetic field to a thickness sufficiently thick that the easy axis of magnetization is oriented parallel to the first axis.

A magnetoresistive read sensor based on the spin valve effect in which a component of the read element resistance varies as the cosine of the angle between the magnetization directions in two adjacent magnetic layers is described. The sensor read element includes two adjacent ferromagnetic layers separated by a nonmagnetic metallic layer. A layer of nonmagnetic electrically conductive material is deposited adjacent to and in contact with one of the ferromagnetic layers, referred to as a filter layers to form a back or conduction layer which provides a low resistance path for conduction electrons transmitted through the adjacent filter layer. The thickness of the filter layer is selected such that it effectively blocks conduction electrons having spins antiparallel to the direction of magnetization in the filter layer while allowing conduction electrons with parallel spins to be transmitted through the layer into the adjacent back layer. The magnetization of the filter layer is free to rotate in response to an applied magnetic field thereby effectively varying the electrically resistance to conduction electrons in the back/filter layer. The thickness of the back layer is selected to optimize the sensor parameters being measured and is in a range of about 4.0 A to 1000 A.

Multiple resonant tunneling devices offer significant advantages for realizing circuits which efficiently convert values represented by multivalued number systems to conventional binary representation. In one form of the invention, a number represented by a range-4 base-2 word is converted into a conventional binary word (range-2 base-2) having the same value. The conversion is accomplished by a series of decomposition stages 53, each decomposition stage 53 producing an interim range-4 base-2 word and a binary digit, which becomes one of the digits of the binary output word. Preferably, the decomposition at each stage is accomplished by a set of range-4 base-2 to binary converters 50, each of which operates on a single digit of the interim word. Preferably, summation circuits 52 sum outputs of adjoining range-4 base-2 converters 50 to form the new interim word. The least significant digit of the output of the decomposition stage becomes a digit of the output binary word. Preferably, the range-4 base-2 to binary converters 50 are multi-level folding circuits 54 connected by a voltage divider. Preferably, the multi-level folding circuits contain multiple-peak resonant tunneling transistors 56 (e.g. an FET 58 and a multiple-peak resonant tunneling diode 60) which exhibit multiple negative differential transconductance. The novel circuits presented allow the results of multivalued logic operations to be translated to binary representation at very high speed. Additionally, because they make use of resonant tunneling devices, the novel converter circuits described herein may be fabricated with very few components.

This is an integrated device which comprises an integrated transistor and resonant tunneling diode where the transistor comprises a substance 10, a buffer layer layer 12 over the substrate 10, and a channel layer 14 over the buffer 12; and the resonant tunneling diode (RTD) comprises a first contact layer 18, a first tunnel barrier layer 20 over the first contact layer 18, a quantum well 22 over the first tunnel barrier layer 20, a second tunnel barrier layer 24 over the quantum well 22, and a second contact layer 26 over the second tunnel barrier layer 24. Other devices and methods are also disclosed.

A spin valve magnetoresistive (MR) sensor uses a multifilm laminated pinned ferromagnetic layer in place of the conventional single-layer pinned layer. The laminated pinned layer has at least two ferromagnetic films separated by an antiferromagnetically coupling film. By appropriate selection of the thickness of the antiferromagnetically coupling film, depending on the material combination selected for the ferromagnetic and antiferromagnetically coupling films, the ferromagnetic films become antiferromagnetically coupled. In the preferred embodiment, the pinned layer is formed of two films of nickel-iron (Ni-Fe) separated by a ruthenium (Ru) film having a thickness less than approximately 10 ANGSTROM . Since the pinned ferromagnetic films have their magnetic moments aligned antiparallel with one another, the two moments can be made to essentially cancel one another by making the two ferromagnetic films of substantially the same thickness. As a result, there is essentially no dipole field to adversely affect the free ferromagnetic layer, which improves the sensitivity of the sensor and allows higher recording density to be achieved in a magnetic recording data storage system.

A self-addressable, self-assembling microelectronic device is designed and fabricated to actively carry out and control multi-step and multiplex molecular biological reactions in microscopic formats. These reactions include nucleic acid hybridization, antibody/antigen reaction, diagnostics, and biopolymer synthesis. The device can be fabricated using both microlithographic and micromachining techniques. The device can electronically control the transport and attachment of specific binding entities to specific micro-locations. The specific binding entities include molecular biological molecules such as nucleic acids and polypeptides. The device can subsequently control the transport and reaction of analytes or reactants at the addressed specific microlocations. The device is able to concentrate analytes and reactants, remove non-specifically bound molecules, provide stringency control for DNA hybridization reactions, and improve the detection of analytes. The device can be electronically replicated.