Abstract: A Silicon-on-Insulator (SOI) field effect transistor (FET) operates in the enhancement mode without requiring inversion by setting the device's threshold voltage to twice the Fermi potential of the thin semiconductor layer in which the transistor is fabricated. The FET, referred to as a Fermi Threshold SOI FET or Fermi SOI FET, has a threshold voltage which is independent of oxide thickness, channel length, drain voltage and substrate channel doping. The vertical electric field in the substrate channel becomes zero, thereby maximizing carrier mobility, and minimizing hot electron effects. The thin silicon layer in which the devices are formed is sufficiently thick such that the channel is not fully depleted at pinch-off. A high speed device, substantially independent of device dimensions is thereby provided, which may be manufactured using relaxed groundrules, to provide low cost, high yield devices.

Abstract: A logic and memory family using CMOS technology operates at high speeds using a Ring Segment Buffer to couple logic gates to one another in an integrated circuit chip, and to couple memory cells to other circuits to provide shift registers, triggers, clock pulse generators and other memory related circuits. The Ring Segment Buffer comprises one or more serially connected complementary field effect transistor (FET) inverter stages, with the output of a preceding stage being connected to the input of a succeeding stage. The N-channel FET in each inverter stage has a channel width which is less than a predetermined factor (K) times the width of the N-channel of the immediately preceding stage. By maintaining the K channel width relationship, the Ring Segment Buffer can drive large capacitive loads at high speed. The Ring Segment Buffer may also provide a predetermined delay which is a function of channel length and the number of stages.

Abstract: A logic and memory family using CMOS technology operates at high speeds using a Ring Segment Buffer to couple logic gates to one another in an integrated circuit chip, and to couple memory cells to other circuits to provide shift registers, triggers, clock pulse generators and other memory related circuits. The Ring Segment Buffer comprises one or more serially connected complementary field effect transistor (FET) inverter stages, with the output of a preceding stage being connected to the input of a succeeding stage. The N-channel FET in each inverter stage has a channel width which is less than a predetermined factor (K) times the width of the N-channel of the immediately preceding stage. By maintaining the K channel width relationship, the Ring Segment Buffer can drive large capacitive loads at high speed. The Ring Segment Buffer may also provide a predetermined delay which is a function of channel length and the number of stages.

Abstract: A high speed, high density, low power dissipation all parallel FET logic circuit includes a driving stage having a plurality of parallel FETs of a first conductivity type for receiving logic input signals and a load FET of second conductivity type connected to the common output of the driving stage. A complementary FET inverter including serially connected FETs of first and second conductivity type is connected to the common output and the load FET. According to the invention the voltage transfer function of the complementary inverter is skewed so that the product of the carrier mobility and the ratio of channel width to length of the inverter FET of the first conductivity type is made substantially greater than the product of the carrier mobility and the ratio of channel width to length of the inverter FET of the second conductivity type. By skewing the voltage transfer function of the complementary inverter the voltage lift-off interval is dramatically decreased, thereby improving the speed.

Abstract: A field effect transistor (FET) operates in the enhancement mode without requiring inversion by setting the device's threshold voltage to twice the Fermi potential of the semiconductor material. The FET, referred to as a Fermi Threshold FET or Fermi-FET, has a threshold voltage which is independent of oxide thickness, channel length, drain voltage and substrate doping. The vertical electric field in the channel becomes zero, thereby maximizing carrier mobility, and minimizing hot electron effects. A high speed device, substantially independent of device dimensions is thereby provided, which may be manufactured using relaxed groundrules, to provide low cost, high yield devices.Temperature dependence of threshold voltage may also be eliminated by providing a semiconductor gate contact which neutralizes the effect of substrate contact potential.

Abstract: A field effect transistor (FET) operates in the enhancement mode without requiring inversion by setting the device's threshold voltage to twice the Fermi potential of the semiconductor material. The FET, referred to as a Fermi Threshold FET or Fermi-FET, has a threshold voltage which is independent of oxide thickness, channel length, drain voltage and substrate doping. The vertical electric field in the channel becomes zero, thereby maximizing carrier mobility, and minimizing hot electron effects. A high speed device, substantially independent of device dimensions is thereby provided, which may be manufactured using relaxed groundrules, to provide low cost, high yield devices.Temperature dependence of threshold voltage may also be eliminated by providing a semiconductor gate contact which neutralizes the effect of substrate contact potential.

Abstract: A three terminal differentially sensitive magnetic diode structure is described. It offers high magnetic sensitivity and utilizes the Lorentz field potential modulation of injected carriers at the emitter. Two base contacts separated from the emitter are employed to derive a signal from the modulation of emitter injection in the presence of a magnetic field.

Abstract: A simplified structure for a single track read/write head design is disclosed. The design incorporates a simplified write coil structure and an improved and simplified combined magnetic bias and sensor current structure. The active sensing current is utilized both to create an anti-parallel magnetic vector couple in a coupled film magneto resistive sensor and to magnetically bias or torque the anti-parallel couple so that magnetization within the sensor films lies at an angle with the easy magnetic axis. Sensor current is fed in series through an electro-magnetic coil wrapped about the magneto resistive sensor so that sense current simultaneously creates an anti-parallel magnetic vector couple in the sensor and generates an electromagnetic bias field to torque the anti-parallel couple at an angle with the easy axis of magnetization.

Abstract: A single track read/write head design is disclosed in which a pair of solid state magnetically permeable sensors such as coupled film magneto resistive sensors are joined together with a central flux conducting probe in the general form of a T or Y connection with the probe extending downward toward a magnetic record medium to conduct flux to or from the medium for writing or reading therefrom. Alternatively, a single coupled film magneto resistive sensor may be bifurcated at its central area at the intersection with the flux coupling probe. The resultant flux coupled from the magnetic medium is divided between the two sensors, or two halves of a sensor, where it alters the magneto resistive or other magnetic property of the sensor in a differential sense, i.e., the left half or left sensor will experience an increase or decrease in resistance while the right half or right sensor experiences an opposite decrease or increase in resistivity, respectively.

Abstract: Track misregistration between a read-back head and a previously recorded pair of tracks can cause erroneous data to be detected by the read head. It has been discovered that a prior erasure to eliminate any residual magnetization reversals occurring between and along side of the two parallel data tracks in twin track vertical recording can unexpectedly increase track misregistration tolerance by several hundreds of percents over the tolerance exhibited by twin track vertical recording having no pre-write erasure in the space between tracks and along side of the tracks. The erase before write technique may be practiced with a new read-write head structure having an E-shaped erase core aligned with the twin track read-write head and insulated from it to precede the read-write structure in the direction of relative motion between the read-write head structure and the magnetic medium.

Abstract: An improved twin track read/write head structure that is differential in its response, thereby eliminating common mode noise signals is described. It also has a low electrical offset, increased linearity and reduction or elimination of any bias fields interfering with the magnetic recording medium. The structure utilizes a dual coupled film magneto resistive sensor bridging the legs of two magnetically permeable coupling members so that the dual magnetic sensors are in a series magnetic circuit with the coupling members. The dual coupled film magnetic sensors are connected together in a center tapped arrangement and are oppositely magnetically biased. Opposing voltages changes occur when the pair are subjected to a magnetic flux field passing serially through them. This produces a differential output signal that rejects unwanted common mode noise of all types.

Abstract: This invention is an improvement in the design of a twin-track read/write heads. The present design eliminates the reluctance gap between the U-shaped write drive coil structure and the U-shaped magnetic sensor and coupling leg structure in that patent. A new structure incorporating two separate coupling legs with a gap at the pole tip interface to the magnetic recording medium for reading and writing is utilized. The new design also incorporates a back gap to adjust the overall reluctance and proportional effect of flying height gap variations. In addition, magnetic shields are introduced to further reduce the effects of fringe field interference at the write head to media interface.

Abstract: Metal junction contact diode and transistor configurations that exhibit high magnetic sensitivity are described. Implanted emitters that have a perimeter area giving rise to unwanted components of minority carrier injection are eliminated in the junction which is limited to a uniplanar contact. Metal semiconductor junctions formed on P-type silicon have been discovered to be superior injectors for minority carriers when hafnium, zirconium, or zinc metal are used to form a silicide layer that forms a reliable emitter. Extreme high frequency capability linear response exist for these devices. They are operative between 0 hertz and 10 gigahertz.

Abstract: Disclosed is an improved method and apparatus for sensing magnetic reluctance variations. The invention may be used for magnetic ink character reading, such as is employed on bank checks, or for any of a variety of magnetic reluctance pickup applications. An improved magnetic reluctance sensor head utilizes an essentially U or C-shaped magnetically permeable member having a magnetizing coil encircling it. The coil is arranged to deliver essentially a constant magnetic flux to the U or C-shaped member. The tips of the U or C are placed adjacent to the element whose variation of reluctance is to be detected and a magneto resistive or other similar magnetic sensor is connected in the magnetic circuit either in parallel or in series with the variable reluctance which is to be sensed.

Abstract: Magnetically sensitive transistors utilizing a newly discovered transduction mechanism are described. The transduction mechanism is Lorentz field potential modulation of carrier injection at the emitter-base junction. Either avalanching or non-avalanching collectors are utilized in a structure having a single emitter and at least one but preferably two collectors. The emitter-base junction is forward biased to inject carriers and the collector-base junctions are reverse biased to collect carriers. Carrier injection is modulated by a Lorentz field. The Lorentz field is produced across the injecting surface of the emitter by interaction between the moving injected carriers by intersection with a magnetic field according to the Lorentz principle. The Lorentz field biases a portion of the emissive surface to inject more heavily and biases the remaining portion to inject less heavily. The carriers streaming toward the separate collectors are thus more heavily concentrated for one collector than the other.

Abstract: Servoing is accomplished utilizing the same read head and the same data track by utilizing a differentially sensitive magnetic sensor. The sensor is utilized as the data read back head sensitive element but separate outputs from the differential sensor are supplied to separate track following amplifiers isolated from the data signal amplifier. The separate amplifiers for the servo information utilize the inherent differential sensitivity of the sensor. As one-half or the other of the differentially sensitive sensor drifts over the edge of a recorded data track, its signal output level will follow. This differential between the left and right halves of the sensor in the form of a change in signal level at the output can be amplified, referenced to common ground for high common mode noise rejection, and a differential signal derived from the difference between the left and right halves of the sensor.

Abstract: The invention discloses a twin track servoing method and apparatus useful for vertical magnetic media recordings. Vertical magnetic media are those in which the magnetic vector in the medium is oriented perpendicular to the surface of the medium instead of lying laterally or longitudinally in the surface of the medium. There are two servo tracks of essentially constant and opposite magnetic polarity recorded on the vertical magnetic medium for each data channel on the medium. The servo tracks themselves may be segmented into reference zones and control or guard zones and they may be recorded on a dedicated surface of a magnetic medium or on the same surface as the data and interleaved with data tracks. When the servo tracks are alternated with data tracks on the same surface of the medium, a single read/write head for twin track recordings may be used to simultaneously read servo signals and data signals.

Abstract: An improved read-write head for twin track vertical magnetic recording is described. Inductive, solid state, or magneto-resistive sensors may all be employed with the new read-write head structure. A preferred embodiment utilizing a magneto-resistive coupled film sensor for read back which saturates to allow writing is disclosed.

Abstract: This invention utilizes a sectored servo control having dual servo tracks recorded in the servo sector. In addition, the servo sector track portions have been recorded with two 180.degree. flux reversals in each track's polarity. The tracks are generally recorded with DC recording current to set a uniform magnetic polarity. The current is switched twice, i.e., from positive and negative and back again or vice versa for each servo track within the servo sector interval. This permits separation of the sensor, amplifier and servo signal offset voltages from the main servo signal itself. Two samples of the servo control voltage are taken during the servo sector interval and the polarity reversal of the servo track is necessary to allow separation of the offset voltages from a variety of sources from the off track or servo error signal.

Abstract: An improved generic form of magnetic read head design is described. Several versions of designs for reading the vertical component of magnetization from a recorded magnetic medium, where data is written in the form of magnetic polarity reversals of transitions, are described. All of the designs utilize the principle of coupling of complementary magnetic poles from the medium to the sensor to improve the magnitude of magnetic field experieced by the sensor. All the designs also utilize two coupling legs arranged in vertical relationship to the recording medium. The legs are relatively widely spaced apart to have their ends proximate to complementary magnetic pole transitions on the medium for a given density of data (expressed as flux changes per inch). The other ends of the coupling legs are brought close together to direct the coupled field from the medium through a narrow gap in which a magnetic sensor is located.