David C Bullock

US Patent:

41931246, Mar 11, 1980

Filed:

Mar 20, 1978

Appl. No.:

5/888124

Inventors:

David C. Bullock - Dallas TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11C 1908

US Classification:

365 12

Abstract:

Input swap transfer/replicate gate and output replicate gate for use in a magnetic bubble memory arrangement between the bubble storage loops and the input and output sections respectively on opposite sides thereof. The input swap transfer/replicate gate and the output replicate gate are of double level construction, each type of gate including a hairpin element at the first level and mounted on a planar layer of bubble-supporting magnetic material on which bubble propagation elements of magnetically soft material are disposed. The bubble propagation elements are arranged to form propagation paths defining a bubble input section, a bubble output section, and a plurality of closed storage loops defining a bubble storage section interposed between the input and output bubble sections. The second levels of the swap transfer/replicate gate and output replicate gate are situated at the input and output ends of the storage loops, forming the opposite bights of the loop. Each type of gate at the second level comprises an asymmetric hook-like transfer/replicate element whose opposite ends are respectively disposed in the opposite courses of the storage loop of which it forms a bight.

US Patent:

41569350, May 29, 1979

Filed:

May 10, 1977

Appl. No.:

5/795475

Inventors:

David C. Bullock - Dallas TX
Robert E. Fontana - Dallas TX
James T. Carlo - Richardson TX
Shalendra K. Singh - Dallas TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11C 1908

US Classification:

365 15

Abstract:

Magnetic bubble domain memory circuit in which magnetizable overlay patterns of magnetically soft material, e. g. permalloy, are provided as bubble propagation elements on a bubble-supporting magnetic layer to define major and minor bubble propagation paths. The major bubble propagation paths provide interchangeable bubble input and output sections, and the minor bubble propagation paths are in the form of closed storage loops providing a bubble storage section comprising first and second pairs of blocks. Bubble generators are provided for each of the blocks included in the first and second pairs thereof comprising the bubble storage section, along with first and second detectors and input/output tracks of bubble propagation elements associated with the respective pairs of blocks of storage loops. Swap transfer/replicate gates are disposed between the input/output tracks and each of the storage loops included in the blocks of storage loops. These gates are alternately operable in a swap transfer mode and a replicate mode so as to simultaneously transfer data as represented by magnetic bubbles and voids from the tracks to the storage loops and from the storage loops to the tracks when operated in a swap transfer mode, and to split respective magnetic bubbles incident thereon in a replicate mode to form a duplicate magnetic bubble in addition to the original magnetic bubble so as to preserve the data intact in the minor storage loop while delivering a bubble to a detector for readout.

US Patent:

42996805, Nov 10, 1981

Filed:

Dec 31, 1979

Appl. No.:

6/108888

Inventors:

Robert E. Fontana - Dallas TX
David C. Bullock - Dallas TX
Shalendra K. Singh - Dallas TX
John M. Bush - Plano TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

C23C 1500
C23F 102

US Classification:

204192E

Abstract:

Method of fabricating a magnetic bubble memory device in which the magnetizable upper overlay pattern of magnetically soft material, e. g. permalloy, defining bubble propagation elements and bubble function-determining components as located above a bubble-supporting magnetic film is disposed in a wholly planar configuration to avoid bubble propagation anomalies encountered with typical non-planar overlay patterns of magnetically soft material. The fabrication method provides for the consecutive deposition onto a substrate having a magnetic film capable of supporting magnetic bubbles of a layer of non-magnetic electrically conductive material, a layer of insulating material, and a layer of magnetically soft material, such as permalloy. Patterning of the layers then proceeds from the uppermost layer downwardly in stages to form magnetically soft components defining the elements of magnetic bubble propagation paths and magnetic bubble function-determining components as a planar upper overlay pattern from the layer of magnetically soft material, insulation spacers from the layer of insulating material, and control conductors as a planar lower overlay pattern from the layer of non-magnetic electrically conductive material. Patterning of the respective layers is preferably achieved by ion milling of selected portions of the layer of magnetically soft material as defined by a first mask and by sequential plasma etching of selected portions of the underlying layer of insulating material and the layer of non-magnetic electrically conductive material as defined by a second composite mask partially comprising the overlay pattern of magnetically soft material and photoresist material.

US Patent:

40706591, Jan 24, 1978

Filed:

Jun 14, 1976

Appl. No.:

5/695485

Inventors:

David Carl Bullock - Dallas TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11C 1908

US Classification:

365 15

Abstract:

Magnetic bubble domain memory circuit design in which magnetizable overlay patterns of magnetically soft material, e. g. permalloy, are provided on a magnetic bubble-supporting magnetic layer to define bubble propagation paths including transfer gate elements and combined replicate/transfer gate elements. The replicate/transfer gate elements are operable in two modes either combining the replicate and transfer bubble functions in a first mode or operable to effect a bubble transfer function in a second mode, wherein a magnetic bubble is transmitted from one section of a bubble circuit propagation path to another. Processing of data through the use of the magnetic bubble domains may occur in a first-in/first-out basis in one embodiment and on a last-in/last-out basis in another embodiment of the bubble memory. A pulse generator is associated with the transfer gate and the replicate/transfer gate structures. The pulse generator associated with the replicate/transfer gate elements is controlled to deliver pulses in two different modes for respectively selectively actuating the replicate/transfer gate elements to perform the composite replicate/transfer function or the transfer function alone.

US Patent:

41527763, May 1, 1979

Filed:

Apr 4, 1977

Appl. No.:

5/783996

Inventors:

David C. Bullock - Dallas TX
Robert E. Fontana - Dallas TX
James T. Carlo - Richardson TX
Shalendra K. Singh - Dallas TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11C 1908

US Classification:

365 12

Abstract:

Magnetic bubble domain memory circuit in which magnetizable overlay patterns of magnetically soft material, e. g. permalloy, are provided as bubble propagation elements on a bubble-supporting magnetic layer to define major and minor bubble propagation paths. The bubble propagation elements are arranged to form major propagation paths defining a bubble input section and a bubble output section respectively. A plurality of minor propagation paths in the form of closed storage loops defining a bubble storage section are disposed between the input and output bubble sections, being arranged in even and odd blocks of minor propagation paths. Input swap transfer gates and output replicate gates are provided between the bubble storage loops and the input and output sections respectively. The input swap transfer gates and the output replicate gates are of double level construction, each type of gate including a hairpin element at the first level and a 90. degree. hook-like element at the second level which is correlated into bubble propagation elements included in a minor storage loop. The 90. degree.

US Patent:

40989178, Jul 4, 1978

Filed:

Sep 8, 1976

Appl. No.:

5/721249

Inventors:

David Carl Bullock - Dallas TX
Mohammed Sabir Shaikh - Dallas TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H01f 1000

US Classification:

427 36

Abstract:

Method of providing a substrate with a patterned metal layer disposed thereon, wherein a patterned metal mask is employed in conjunction with ion milling to form the pattern in the metal layer on the substrate. The metal mask as contemplated herein is made of a metallic masking mterial taken from the group consisting of vanadium, tantalum, titanium, and a titanium-tungsten alloy--vanadium being a preferred material because of its resistance to erosion or etching from ion milling coupled with its relatively fast etch rate in a plasma atmosphere. This method has particular application to magnetic bubble domain technology, wherein successive layers of a magnetically soft material, vanadium, and photoresist are deposited on a magnetic film capable of supporting magnetic bubble domain propagation. The layer of magnetically soft material is typically permalloy, and upon being patterned in a selected configuration, defines a bubble propagation path on the magnetic bubble-supporting film. The photoresist layer is selectively exposed to the predetermined pattern by a source of energy, such as an E-beam, X-ray or ultra violet light.