International Business Machines Corporation

Patrick C Arnett

David C Cheng

Glen Alan Jaquette

Andres Bryant

Richard Leo Galbraith

Jonathan Darrel Coker

Ernesto Esteban Marinero

Sakhrat Khizroev

John S Foster

Jane Elizabeth Frommer

Roger William Wood

David A Thompson

Blair I Finkelstein

David E Call

Yaw-Shing Tang

Radley Wahl Olson

Joseph Juifu Chang

Jon A Iwata

Both the read and write heads are trimmed to approximately 100 nm wide, indicated by Wr and Ww, respectively. The etch depth for the MR element, MR Trenches, is 200 nm and the etch depth for the write head, Write Trenches, is 1 &mgr;m. In order to confirm that inactive regions are actually those selected for irradiation, during trimming the center of the trimmed MR element has been offset by approximately 300 nm from the center of the original MR element. This offset is observed in the final result.

Track width control of readback elements with ions implantation in a bounding region of tip portion to selectively deactivate magnetic sensitivity thereof

A method and a device for write precompensating a data pattern for recording the pattern on a magnetic storage medium at high data rates. A first predetermined write-precompensation delay is applied to the second transition of a burst of transitions of the data pattern. A second predetermined write-precompensation delay is applied to the last transition of a burst. A third predetermined write-precompensation delay is applied to the middle transitions, if any, of a burst. When the burst is a dibit, the application of the second and third predetermined write-precompensation delays is omitted and the first predetermined write-precompensation delay is based on the burst being a dibit. When the burst is a tribit, the application of the second predetermined write-precompensation delay is omitted and the first and third predetermined write-precompensation delays are based on the burst being a tribit. A fourth predetermined write-precompensation delay is applied to the transitions in the data pattern that are not part of a burst of transitions.

Method for improving magnetic recording at high data rates for waveforms having a burst of transitions

A light intensity, direct overwrite, magneto-optical system generates signals such that, during the formation of a recording mark on an optical disk, a laser is driven a) at a pedestal power level, then b) at a quench power level for a first quench period t.sub.1, the quench power level being less than the pedestal power level, then c) at a write power level for a write period t.sub.2 whereby the reference bit becomes oriented in the writing direction, the write power level being greater than the pedestal power level, then d) at the quench power level for a second quench period t.sub.3, and then e) at the pedestal power level until the formation of another recording mark begins. The system is provided with a controller to determine optimal lengths of the quench periods t.sub.1 and t.sub.3, thereby reducing thermal interference between closely spaced recording marks. From sample recording marks, recorded with different quench periods t.sub.1 and t.sub.3, the controller calculates a 'quality' value, such as bit error rate, jitter or figure of merit, then determines from the quality value the quench periods t.sub.1 and t.sub.3 which will produce the highest quality recording marks.

Magneto-optical recording device capable of reducing thermal

A method and apparatus are provided for determining an adjustable precompensation value in a partial-response maximum-likelihood (PRML) data channel. The PRML data channel includes an adjustable precompensation function for modulating the write data waveform. A predetermined test pattern is written using write circuitry in the disk file. The predetermined test pattern is insensitive to channel misequalization and provides a reference for gain and timing control. The written predetermined test pattern is read back using read circuitry in the disk file. An error in sample values in the read back predetermined test pattern is identified using logic provided in the PRML data channel while performing a standard read operation of a data sector written with the test pattern. The adjustable write precompensation value is adjusted responsive to identifying an error.

Method and apparatus for precompensation value determination in a PRML

A high resolution lithographic mask having a desired pattern is generated and used to replicate the pattern onto a film in a one-step process. A film of phase-changeable material in one state is provided on a conductive substrate. By scanning tunneling microscope techniques, the state and thereby the conductivity or other property of the material in selected areas of the film is changed to a second state to provide from the film a mask having a desired pattern defined by crystalline areas. Amorphous material need not be removed from the mask. To replicate the pattern on another film, the latter is placed on another conductive substrate; the mask is positioned with its patterned side within electron tunneling distance of said other film; and the pattern is replicated in a single step by applying a voltage between the mask and other film. The voltage charge on said mask is positive and negative on said other film to cause current to flow in the crystalline areas of said mask and, by electron flow from said film to the mask, eliminate backscattering and insure high resolution. As the state changes (e.g., from crystalline to amorphous) in the pattern areas of said other film, conductivity in the crystalline areas will progressively decrease and, by causing a corresponding reduction in current flow in the crystalline areas, minimize the risk of undesired broadening of exposed areas of said other film.

Method of making and using a high resolution lithographic mask

An extremely high density memory array in which every intersection between two insulated orthogonal sets of drive lines define a nonvolatile memory device is described. Each device utilizes the area directly under the intersection of sets of lines to selectively store charges therein under control of suitable writing pulses. Reading is accomplished utilizing capacitive coupling through the device. The array comprises insulated metallic word lines orthogonal to doped bit lines defined within the surface of a semiconductor body. The insulation between the word lines and the bit lines has a dual charge state and is capable of storing charges. A unique structure is utilized whereby a highly doped layer is formed at the surface of the semiconductor body and of the same conductivity type as the body. The bit lines are composed of two distinct layers of an opposite conductivity type to that of said body wherein the layer closest to the surface is less highly doped. The selective biasing of word and bit lines causes charges to be injected into the insulation immediately between the two lines which injected charges alter the capacitance characteristics of the device and thus the signal coupling characteristic between the word and bit lines. During the write operation, an avalanche breakdown at the junction is caused to occur by heavily biasing the junction, and charge carriers are injected into the overlying insulator. The charge carriers so injected remain localized in the insulator immediately between the two lines with negligible fringing into the region outside this intersection and thus do not disturb the information on adjacent bit lines which allows extremely close placement of such adjacent lines. To erase, a voltage is supplied to cause the injected carriers to be driven out of the insulation back into the substrate. As stated previously, the reading operation utilizes the change in the coupling capacitance with a charge stored in the device and comprises introducing a signal on one line well below the breakdown voltage of the device so that the stored charge is in no way affected by any number of reading operations and detecting said signal on the other line, if coupled through.

Ultimate density non-volatile cross-point semiconductor memory array

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Morgan Hill, CA, United States of America

Patrick C Arnett