Abstract: A method for etching materials in which a solid, located in the vicinity of the substrate, is used to provide reactive species for etching the substrate. In contrast with prior art etching techniques, an ion beam is provided which strikes a solid source located in the vicinity of the substrate. Reactive gas species are given off by the solid source when it is hit by the ion beam and these species etch the substrate. Etch rates can be enhanced or retarded depending upon the composition of the solid mask. The process has particular utility in etching generally active metals such as Ti, Nb, Ta, NiFe, etc. which undergo a large change in etch rate when mixed gases, such as argon plus O.sub.2, CF.sub.4, CO, or CO.sub.2 (singularly or in combination) are used. As an example, solid TEFLON* can be used to surround the substrate during etching in order to generate active species, such as C and F, for etching of materials such as Ti, Si, NiFe, etc. Conductors and dielectrics can also be etched by this technique.

Abstract: A magnetic bubble domain chip having two levels of metallurgy fabricated in a single masking step and including a replicate type bubble generator. The bubble generator includes a magnetic disk which holds a seed domain during reorientation of a magnetic drive field in the plane of the magnetic bubble material, and a conductor located at the leading, i.e., cutting, edge of the magnetic disk. Current in the conductor is used to assist the splitting operation whereby a new domain is split from the stretched seed domain. The conductor includes a first portion having a relatively wide cross-section where most of the current flows through a highly conductive material, such as gold. In the area of the generator, the conductor is narrow and the current path is through the magnetic material comprising the disk.

Abstract: A magnetic bubble domain storage system comprising an array of rows and columns of logical chips are organized into logical half-chips with even numbered bits in one half-chip and odd numbered bits in the other half-chip. Alternating rows of half-chips are used for storing even numbered bits and odd numbered bits, respectively. Each half-chip has its own bubble domain generator, but a common generator current line serves all generators for a row of even half-chips and all generators for a row of odd half-chips. Thus, information is written into even half-chips and odd half-chips at the same time by pulsing the generator current line common to a row of even half-chips and a row of odd half-chips. Each half-chip has a sensing element and all the sensing elements corresponding to a row of half-chips are connected in series.

Abstract: A relational data base system using magnetic bubble domain storage to eliminate data formatting, and dynamic indexing loops to facilitate convenient marking during data qualification and to eliminate redundant traversing of disqualified data during the search operation. A data base is stored in columnized storage tables which insure minimum input/output data traffic during search and retrieval. A suitable storage chip is organized in a major/minor loop organization, with several sections of transfer lines to provide selective access to individual groups of storage loops. Off-chip circuitry includes a comparator for comparing data read from a bubble storage chip with a given criterion in order to select appropriate data, and a dynamic indexing loop which keeps track of comparisons. This indexing loop provides an input to a bubble chip controller so that each subsequent search and compare is done only on already qualified data. This eliminates the need for repeated searching through the same data.

Abstract: A chemical vapor deposition (CVD) process is described for depositing magnetic oxides, such as garnets, having growth induced anisotropy sufficient to support stable bubble domains, even in very thin films. Organometallic source compounds are used together with low growth temperatures less than 900.degree. C. and high nozzle velocities in the range of 200-600 cm/sec. at room temperature. The oxidant gas mixture contains about 30-50 mol percent O.sub.2, rather than approximately 100 mol percent O.sub.2, as is usually used in CVD processes for depositing magnetic garnet films. The gas flow is transverse to the plane of the substrate onto which deposition is to occur, and is preferably perpendicular to the plane of the substrate. The individual source compounds are volatilized and carried by an inert gas, combined, then pre-mixed with oxygen in a nozzle without reaction at about 200.degree.-300.degree. C. The gas mixture is then passed at high velocity (200-600 cm/sec) onto a heated substrate.

Abstract: An improved magnetic bubble domain chip and processes for making the chip are described. The chip is comprised of a magnetic bubble domain film in which small bubble domains can be moved, and overlying layers of metallurgy. The layer of metallurgy closest to the bubble film is an electrically conductive layer having apertures (or recesses) therein. This layer is patterned to provide current carrying conductors. The next overlayer is a layer of magnetic material having in-plane magnetization which is patterned to provide the propagation elements used to move the bubble domains. In a particular embodiment, the magnetic layer is comprised of a magnetically soft material, such as permalloy. The chip is characterized by the provision of insulating pedestals located in the apertures of the conductive layer. These insulating pedestals are located in the regions of the chip used for sensing (and/or bubble generation). That is, they take the place of the thick conductive material in those areas of the chip.

Abstract: A two-dimensional storage system having two dimensional access is described which offers advantages of speed and effective utilization of available storage area. The system is comprised of a plurality of bubble domain storage arrays, each of which has means therein for moving bubble domains in two dimensions. For instance, in each storage array bubbles can be moved either right-left or up-down. A functional area is provided between adjacent storage arrays to accommodate bubble movement to perform read, write, and clear functions and possibly logic functions. In one embodiment, the functional areas are comprised of sensors which simultaneously function as translation elements to map the information in one storage array into an adjacent array. Magnetic bubble domain sensors are provided for detecting bubble domains moved in one or two dimensions. For example, one sensor can be used to detect bubble domains moving right-left while another sensor is used to detect bubble domains moving up-down.

Abstract: These improved current controlled transfer switches are particularly useful for changing the propagation path of very small bubble domains without requiring large amounts of transfer current. The underlying principle is that the transfer operation occurs when the magnitude of the magnetic drive field used to move bubble domains has diminished to a small value, or is zero. This means that the magnetic field due to current in the switch does not have to overcome the effect of the drive field and therefore can be very small while still being effective. This is termed a "start/stop" operation and in one embodiment, current-assisted transfer is achieved by utilizing a change in the sequence of the magnetic drive field (generally an in-plane rotating field) at the time of transfer. In another embodiment, a continuous "three-quadrant" magnetic drive field is used instead of the customary 360.degree. rotating drive field.

Abstract: Device having three semiconductor regions, which can be characterized as the emitter, base and collector regions. The emitter and collector regions have a first conductivity type, and the base region has the opposite conductivity type, where both the base-emitter and base-collector junctions are heterojunctions. The base region is sufficiently thin that charge carriers can tunnel therethrough. The base region has a small resistance due to its heavy doping (which is greater than the doping of both the emitter and the collector). Both the valence band and the conduction band in the emitter and collector regions are shifted in the same direction with respect to the valence band and conduction band of the base region (i.e., the energy gaps of the emitter and collector are shifted in the same direction with respect to the energy gap of the base region and overlap with the energy band of the base to produce band-edge discontinuities .DELTA.E.sub.c and .DELTA.E.sub.v).

Abstract: A magnetic bubble storage system and a method for making it using only two masking steps, one of which is critical. In a preferred embodiment, the storage regions are comprised of ion implanted propagation elements which can be contiguous with one another. The functions of write, read, storage, transfer between storage elements in different shift registers, and annihilation are provided by the method in which the same mask is used to define ion implanted regions and for formation of conductor metallurgy. Permalloy bridges over ion implanted regions are used to provide transfer of information between one storage element and another. In a preferred embodiment, NiFe is used for sensing, annihilation, and transfer of information, while the storage registers are comprised of ion implanted regions defining contiguous propagation elements of generally circular geometry.

Abstract: A bubble domain storage system is described which has the best features of contiguous element bubble propagation systems and bubble lattice file systems. An array of magnetic bubble domains, such as a lattice, is moved along contiguous propagation patterns in response to the reorientation of a magnetic field in the plane of the bubble domain film. Adjacent rows of bubble domains in the array move in opposite directions to provide individual storage loops within the array. Information accessing can be achieved by the use of input/output registers similar to those used in other contiguous disk bubble domain storage systems. For example, the storage system can be a conventional major/minor loop organization using contiguous element propagation patterns for the storage registers and for the input/output registers.

Abstract: A switch for transferring magnetic bubble domains from one propagation path to another using a magnetic charged wall is described. The magnetic charged wall bridges the two propagation paths and causes the domain to strip out along the charged wall. By pulsing an overlying conductor, the charged wall and the associated strip domain will shrink away from one side of the conductor in order to translate the domain to the other side. In contrast with previous transfer gates using current carrying conductors where the magnetic field produced by current through the conductors served as the major bubble translational force, the present switch utilizes a magnetic charged wall as the driving source, the current through the conductor being used only for modification of the charged wall. Therefore, the switching margins are maximized to be substantially the same as the bubble propagation margins and the switching currents required are reduced from those in previously used transfer gates.

Abstract: An improved magnetic bubble domain nucleator is provided which uses a magnetic wall, such as a charged wall, Neel wall, or Bloch wall, to assist nucleation. In a preferred embodiment, a magnetic charged wall is produced in an ion implanted region of a magnetic material with an in-plane magnetic field, and an applied nucleating magnetic field is produced by current in a conductor. The combination of the first magnetic field associated with the charged wall and the second magnetic field produced by current through the conductor is sufficient to nucleate a bubble domain in the magnetic medium whereas each of these fields acting alone is not sufficient for nucleation. Since the first magnetic field provides a component of the total nucleating field, the amount of nucleation current required in the conductor is reduced.

Abstract: A relational data base system utilizing magnetic bubble domain storage. The bubble domain storage is located on a magnetic chip and includes storage circuitry for storing bubble domains in columns and rows. The bubble domains are coded to represent data, and the rows and columns of bubbles correspond to tables of data which are determined by various relations. Current activated transfer gates located on the magnetic chip are used to select a particular row or a particular column of bubble domains for accessing. The magnetic chip also includes a write circuit for writing bubble domains into storage and a read circuit for reading bubble domains removed from storage. Located off the magnetic chip are column addressing circuits, row addressing circuits, interface circuitry, and a computer central processing unit.

Abstract: A structure and technique are provided for improving the average access time in a bubble lattice file (BLF) storage, and for providing reordering capability in the lattice file. The bubble lattice arrangement includes a translation structure for moving bubble domains in the lattice to various access channels where columns of bubble domains can be removed from the lattice. These are double access channels which remove two adjacent columns of bubble domains at the same time. A read means and a write means are associated with each channel of the double channel access for reading the information in each column removed from the lattice, and for writing new information into these columns. A transposition structure is provided for transposing the information represented by bubble domains in each of the removed columns, in response to a signal from associated control circuitry.

Abstract: Magnetic bubble domains are propagated in a magnetic medium in a desired direction using in-plane magnetic fields which are time varying but which have no spatial gradients. In applications such as information storage, the need for conventional propagation structures, such as offset conductor loops, patterned magnetic elements, and patterned ion implantation regions is reduced. Bubble domains having unwinding pairs of Bloch lines in their wall magnetization can be moved by applying appropriate in-plane magnetic fields, without the need for spatial gradients or variations in the magnetic field normal to the plane of the magnetic medium. The continuous movement of these bubble domains occurs by a cyclic process where the Bloch lines switch between two configurations, in an asymmetric way in response to the time varying in-plane field.

Abstract: A semiconductor memory (storage) device is provided using layered semiconductor structures which produce spatially separate electron and hole wells. The state of the device depends upon whether or not charge carriers (electrons and holes) are confined in these wells. Thus, the device has a first state exhibiting one conductance or capacitance when the wells do not have charge carriers in them, and a second state (different conductance or capacitance) when charge carriers are confined in the potential wells. The lifetime of the state in which carriers are confined in the wells depends upon the amount of time required for electron-hole recombination and is expected to be very long since the electrons and holes are spatially separated. A preferred embodiment utilizes a layered heterostructure formed in the space charge region of a p-n junction.

Abstract: An improved ion implanted propagation structure for movement of magnetic bubble domains in a storage medium which comprises an additional magnetic layer capable of ion implantation in combination with a bubble domain storage layer in which the bubble domains exist and are moved by the ion implanted layer in response to the reorientation of a magnetic field in the plane of the ion implanted layer. The ion implanted layer (drive layer) can be in intimate contact with the storage layer and exchange coupled thereto, or can be separated from the storage layer by a non-magnetic spacer. The ion implanted layer can comprise different geometry propagation elements and its thickness, 4.pi.M, and other magnetic properties are generally selected to provide flux matching of a charged wall in the ion implanted layer with the flux emanating from the bubble domains to be moved. The charged wall is coupled to the bubble domain by exchange coupling and/or magnetostatic coupling. SUBACKGROUND OF THE INVENTION1.

Abstract: A technique for controllably providing state conversions between bubble domains having a common winding number S is described. In particular, controlled conversions between bubble domains having winding number S=1 is achieved by the application of spatially invariant, homogeneous magnetic fields. For the conversion of .sigma. bubbles (having two vertical Bloch lines) to .chi. bubbles (having no vertical Bloch lines), an in-plane field is not required and only a time varying perpendicular z-field is used. For conversion of a .chi..sub.+ bubble to a .chi..sub.- bubble, and vice versa, a time varying field pulse is applied, there being no requirement for an in-plane magnetic field. However, for the conversion of .chi. bubbles to .sigma. bubbles, an in-plane field is used simultaneously with a time varying z-field. For all controlled conversions, the applied magnetic fields do not have spatial gradients.

Abstract: Propagation of a lattice of magnetic bubble domains by field access techniques is achieved by using a periodic array of magnetic chevron elements. In response to the reorientation of a magnetic drive field in the plane of the chevron elements, magnetic poles are established to directly drive the lattice bubble domains. Those lattice domains not directly driven by magnetic poles are driven by repulsive forces within the lattice, such as those due to bubble-bubble interactions. The chevron arrays are designed to conform to the bubble lattice framework and patterns are established in which multiple bubble domains are associated with each chevron. The chevron elements can be symmetrical elements or skewed elements, and patterns are provided which can be used to drive multiple rows or columns of bubbles per chevron row or column. Generally, bubble domains alternate between being directly driven by magnetic poles along the chevrons and being indirectly driven by repulsive forces in the lattice.