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1.
A permalloy disk replicator in an amorphous film 2 μm bubble device has been Studied for different geometrical dimensions, and from quasi-static to 200 kHz operating frequency. Distinct regions of the margin plot are observed, and their dependence on geometry is analyzed. It is found that for reliable replication over a wide margin range, the poles from the replicator disk, from the neighboring propagation channel, and from the previously replicated bubbles must be carefully balanced. A replicator with 20% margins on 2-micron GdCoMo films is shown and methods for further improvements are discussed. 相似文献
2.
The applications of magnetic bubbles that are currently seen as most attractive and the current status of development of such devices are considered. A major application is thought to occur in solid-state mass memories. An attractive form of organization is possible whereby relatively short access times can be achieved while using only a small number of read and write circuits. A repertory dialer memory, which has been chosen as a test vehicle, has been developed. The design and performance of the propagating circuits, the self-latching magnetic gates and the generator, which comprise the memory, are discussed. A novel area of application may be in pulse code modulation (PCM) switching networks. It is shown how a network operating as a PCM crossbar switch can be designed using bubbles. A circuit is described which can eliminate the delay associated with bubble propagation in such networks. 相似文献
3.
Contiguous-disk bubble devices are an approach to higher bit density through the use of coarse overlay patterns in manipulating small bubbles to relax device lithography requirements. As a first step towards such an objective, a fully processed chip using ion-implanted devices has been tested, showing the feasibility of all required memory functions with 5-μm bubbles and 25-μm period overlay patterns. A critique of permalloy versus implanted contiguous-disk devices is made, pointing out their basic difference in magnetization reversal processes and explaining the superiority of the latter over the former in achieving a good edge affinity of bubbles. The requirements for a good implanted device are reviewed, including the selection of garnet material parameters (K1 , λ111 ), of implantation parameters (ion energy and dosage) and of device pattern geometry (thickness and shape of implanted layer). An understanding of these requirements has made it possible to demonstrate 1-μm bubble propagation in several contiguous-disk type circuits with 4.5-μm periods, yielding an areal density of over 3 × 107bit/in2made by conventional photolithography. 相似文献
4.
Magnetic bubble shift register devices of 68 121- and 266 473-bit capacity have been fabricated and tested. The epitaxial garnet bubble films were nominally 1.7 μm thick, supported nominally 1.7-μm diameter bubbles, and had collapse fields of about 260 Oe. The storage area per bit was 64 μm2, which was realized with a minimum coded feature dimension of 1 μm and contact photolithography using EBES chrome masters. Initial yields obtained in two experimental batches each of the two chip capacities are discussed. Parametric test results are presented for generator current, transfer current and phase, and rotating field intensity. Nominal values have been established to be 130-mA generate current, 21-mA transfer current, and 60-Oe drive. The detector signals were about half as large as normally obtained from 3.3-μm bubble devices with comparable resistance and conventional design. 相似文献
5.
Inductively coupled plasma reactive ion etching of CoZrNb magnetic thin films was studied using a TiN hard mask in a Cl2/O2/Ar gas mix. The etch rates of CoZrNb films and TiN hard mask gradually decreased with increasing Cl2 or O2 gas concentrations. When O2 gas was added in the Cl2/Ar gas mix, the etch rate of TiN hard mask was suppressed effectively so that the etch selectivity of CoZrNb film to TiN hard mask was enhanced. The addition of O2 into the gas mix also led to the anisotropic etching of the CoZrNb films and it was confirmed by Auger electron spectroscopy that there were no redeposited materials on the sidewall of the etched films. Highly anisotropic etching of CoZrNb films was achieved at room temperature under the optimized etching conditions. 相似文献
6.
An experimental test set for magnetic bubble devices has been constructed in which the spacing between the garnet film and the Permalloy overlay is variable. The experimental uncertainty in spacing is approximatelypm.15mu m, and spacings as small as.5mu m have been attained. Bias margin data are presented which were taken at 1 Hz on a 20 micron period chevron circuit as a function of spacing. The collapse and strip-out fields begin to be affected when the spacing is comparable to the garnet film thickness, increasing as the spacing decreases. At larger spacing the high-bias failure mode changes from collapse to uncorrelated bubble motion. A theoretical model which accounts for some aspects of the spacing dependence of the strip-out and collapse fields is described. This model approximates the circuit by a continuous Permalloy sheet. At the low spacing required for efficient use of the rotating field, the model indicates that ±10% nonuniformity in a 2 micron spacing over the device area results in a degradation of the bias field operating range by about 12%. 相似文献
7.
Diamond like carbon (DLC) thin films were used as the cathode layers of inorganic alternating current driven thick dielectric electroluminescent devices. The results indicated that electroluminescent (EL) devices with DLC cathode has superior brightness over the EL with Al or Cr-doped DLC cathodes. Cr-doping in DLC thin film can increase the electrical conductivity, but degrades the EL properties. Also, the EL device with DLC cathode possesses the lowest decay rate among various cathodes, because of the high thermal conductivity and the inert nature of DLC film. 相似文献
8.
Permalloy devices with two separate levels of fine permalloy and conductor patterns have been fabricated by the use of a single-mask process. This process makes possible the production of devices having an essentially conventional design in addition to a completely planar structure. The features of this new process include 1) preparation of a reticle on which patterns for both permalloy and conductor layers are superimposed, 2) use of SiO2 , Mo/Au/Mo, SiO2 , permalloy, and TiO2 thin films deposited sequentially on the bubble materials, and 3) simultaneous delineation of both photoresist patterns with two different thicknesses and of the desired patterns by CF4 plasma etching and ion-milling. 相似文献
9.
Adnan Ali Kamran Ali Ki-Rin Kwon Myung Taek Hyun Kyung Hyun Choi 《Journal of Materials Science: Materials in Electronics》2014,25(2):1097-1104
Graphene-based composites represent a new class of materials with potential for many applications. Metal, semiconductor, or any polymer properties can be tuned by attaching it to graphene. Here, a new route for fabrication of graphene based composites thin films has been explored. Graphene flakes (<4 layers) and a well-known semiconductor zinc oxide (ZnO) (<50 nm particle size) have been dispersed in N-methylpyrrolidone and ethanol, respectively. Thin film of graphene flakes is deposited and decorated with ZnO nanoparticles to fabricate graphene/ZnO composite thin film on silicon substrate by electro hydrodynamic atomization technique. Graphene/ZnO composite thin film has been characterized morphologically, structurally and chemically. To investigate electronic behavior of the composite thin film, it is deployed as cathode in a diode device i.e. indium tin oxide/poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate)/polydioctylfluorene-benzothiadiazole/(graphene/ZnO). The J–V analysis of diode device has shown that at voltage of 1 V, the current density in organic structure is at low value of 4.69 × 10?3 A/cm2 and when voltage applied voltage is further increased; the device current density has increased by the order of 200 that is 1.034 A/cm2 at voltage of 12 V. 相似文献
10.
M. A. Uddin W. F. Ho Hau Ping Chan 《Journal of Materials Science: Materials in Electronics》2007,18(6):655-663
One main critical issue in the fabrication of polymer optical devices is the adhesion strength of polymeric layer to the substrate.
High adhesion strength is desirable and critical in order to avoid peeling out of polymeric layer from the substrate due to
stress generated during fabrication, handling and lifetime. Therefore, the aim of this study is to investigate the interfacial
adhesion of polymeric adhesive film on different possible substrate surfaces such as pure silicon wafer, silica on silicon
wafer, and thin metal layer (Chromium–Cr) on silicon wafer under different processing conditions. Surface morphology of the
substrates before deposition was characterized by atomic force microscope (AFM). Adhesive shear button was made on those substrates
by using photolithography process and the interfacial adhesion was measured by using a Dage D2400 shear tester. The effect
of exposing in high temperature and typical damp heat condition on the interfacial adhesion was also studied. We found that
the best adhesion performance was obtained for the case using Cr thin in all processing conditions, especially under heat
treatment and damp heat test. From this study, we suggest that a thin layer of metal film on silicon wafer can be use to improve
the adhesion and the reliability of the polymer photonic devices. The oxidized silica on silicon wafer is an alternative choice
at the expense of reducing adhesion performance. Moreover, using silica layer has the advantage over Cr layer that one fabrication
step can be reduced since the silica layer itself can effectively act as the lower cladding of the devices. 相似文献
11.
An electron-beam writing system that is chartacterized by a stationary electron beam and a continuously spinning table is proposed and developed for diffractive optic elements with axisymmetric patterns. This system allows us to fabricate continuously concentric or radialized high-density microgratings with effective areas over the electron-beam deflection limits. For a fine electron-dose distribution, we adopted multiple-revolution writing and electron-beam modulation. Several test gratings, including a rotary encoder disk with a 1.57-μm grating pitch and a 15-mm diameter and a blazed micro-Fresnel lens with a 4.5-mm diameter and a N.A. of 0.45, are successfully demonstrated with real-time data processing. 相似文献
12.
A two-mask level, conductor first thin film process is described for fabrication of magnetic bubble devices. The process permits a stepless permalloy level over a conductor that may be two to three times as thick as conventional processing The planar process is attained by anodizing a thick aluminum alloy film in all regions where no conductor is needed. The process described solves problems in conventional processing caused by thin conductor metalization and permalloy step coverage. Replication, nucleation, and annihilation devices made with this process promise superior performance. 相似文献
13.
An analysis has been made of the number and types of logical functions which can be performed using the interaction of circular magnetic domains in rare earth iron oxides. Multiple logic functions are found to be produced simultaneously at any logical area. These conjunctive output sets have been categorized. Several conjunctive logic gates have been designed, fabricated, and tested successfully in Sm0.55 Tb0.45 FeO3 using Permalloy overlays. Utilizing a circuit in which AND/OR logic gates are coupled to a dynamic memory bank, the total correlation of two data streams has been performed. It is shown how this multiply accessed dynamic memory serves to establish the correlation threshold. 相似文献
14.
Devices in which the transport and storage of single electrons are systematically controlled could lead to a new generation of nanoscale devices and sensors. The attractive features of these devices include operation at extremely low power, scalability to the sub-nanometre regime and extremely high charge sensitivity. However, the fabrication of single-electron devices requires nanoscale geometrical control, which has limited their fabrication to small numbers of devices at a time, significantly restricting their implementation in practical devices. Here we report the parallel fabrication of single-electron devices, which results in multiple, individually addressable, single-electron devices that operate at room temperature. This was made possible using CMOS fabrication technology and implementing self-alignment of the source and drain electrodes, which are vertically separated by thin dielectric films. We demonstrate clear Coulomb staircase/blockade and Coulomb oscillations at room temperature and also at low temperatures. 相似文献
15.
It is well-known that metallization edge-induced stresses can change the uniaxial magnetic anisotropy of a liquid phase epitaxial (LPE) garnet film near the metallization edge. We have investigated this magnetostrictive interaction of patterned metallic films with ion-implanted LPE films by using several different spacer layers such as polyimide, SiO2 , Si3 N4 , and combinations of polyimide and SiO2 beneath a Cr-Cu-Cr conductor pattern. It is concluded that the stress eliminating capability of a spacer depends on the hardness parameterK = frac{E_{s}(1-numin{f}max{2})}{E_{f}(1-numin{s}max{2})} whereE_{s} , E_{f} are Young's moduli andnu_{s}, nu_{f} are Poisson's ratios for the spacer and metallic film, respectively. The polyimide spacer withE_{s} < 10^{11} dyn/cm2and withK leq 0.1 transmits an order of magnitude of smaller stress than a SiO2 spacer withK geq 1 with the stress being more uniformly distributed across the spacer. 相似文献
16.
We report on a quartz pin that can be interfaced easily to existing pin printers. The new pin surface can be reversibly derivatized using silanization chemistry, allowing one to reliably print a wide variety of liquid solutions. Feature sizes as small as 9 microm can be produced with the new pin, allowing one to readily create microarrays with a feature density approaching 10(6) spots/cm2. 相似文献
17.
S. Duenas E. Casta′n J. Barbolla R. R. Kola P. A. Sullivan 《Journal of Materials Science: Materials in Electronics》1999,10(5-6):379-384
In this work we report on very thin (10 to 100 nm) tantalum oxide fabricated by anodic oxidation of tantalum nitride and tantalum silicide to be used as the dielectric of high density MIM and MIS capacitors. These films exhibit greatly improved leakage currents, breakdown voltage and very low defect density, thus allowing the fabrication of large area capacitors. Several counter and bottom electrodes have been used and compared. The effects of the different processing conditions (top-electrode metals, annealing conditions, bottom electrode stoichiometry) on the capacitor performances are extensively discussed throughout this work. The nitrogen content of tantalum nitride films seems to have an important influence on the insulator quality. Leakage currents in the insulator have been carefully studied in order to determine the nature and physical origin of the dominant conduction mechanisms in the insulator. The electrical behaviour of the resulting high-density MIM capacitors has been extensively characterized. Finally, we describe a new method to fabricate MIS diodes with anodic tantalum oxide as insulator. 相似文献
18.
A study has been made of a system consisting of a pair of magnets with thin plates of permeable material on their inner faces. The effect of the plates on the profile of the field between the magnets is predicted as a function of the geometry and the permeability and the way in which the uniformity can be improved is demonstrated.The effect of the permeability is very limited. 相似文献
19.
The dependence ot the in-plane drive field at which bubble domains spontaneously nucleate in field-accessed bubble devices has been investigated as a function ofH_{k} - 4piM_{s} and of spacer thickness between the bubble film and permalloy propagation elements. The experiments were carried out on amorphous GdCoMo bubble films with T-bar and Y-bar structures. For a given structure and spacer thickness the nucleation field increases linearly withH_{k} - 4piM . Larger spacer thicknesses also lead to increased nucleation fields. A model based on the Stoner-Wohlfarth astroid is compared to these data and found to be useful in explaining the qualitative trends, but to be in poor quantitative agreement. It is concluded that since the drive field required in a device is proportional to4piM_{s}, Q - 1 = (H_{k} - 4piM_{s})/4piM_{s} must be greater than some minimum value for a given device structure and spacer thickness to permit reliable device operation. 相似文献
20.
Watson MW Abdelgawad M Ye G Yonson N Trottier J Wheeler AR 《Analytical chemistry》2006,78(22):7877-7885
Digital microfluidics is a fluid manipulation technique in which discrete droplets are actuated on patterned arrays of electrodes. Although there is great enthusiasm for the application of this technique to chemical and biological assays, development has been hindered by the requirement of clean room fabrication facilities. Here, we present a new fabrication scheme, relying on microcontact printing (microCP), an inexpensive technique that does not require clean room facilities. In microCP, an elastomeric poly(dimethylsiloxane) stamp is used to deposit patterns of self-assembled monolayers onto a substrate. We report three different microCP-based fabrication techniques: (1) selective etching of gold-on-glass substrates; (2) direct printing of a suspension of palladium colloids; and (3) indirect trapping of gold colloids from suspension. In method 1, etched gold electrodes are used for droplet actuation; in methods 2 and 3, colloid patterns are used to seed electroless deposition of copper. We demonstrate, for the first time, that digital microfluidic devices can be formed by microCP and are capable of the full range of digital microfluidics operations: dispensing, merging, motion, and splitting. Devices formed by the most robust of the new techniques were comparable in performance to devices formed by conventional methods, at a fraction of the fabrication time. These new techniques for digital microfluidics device fabrication have the potential to facilitate expansion of this technology to any research group, even those without access to conventional microfabrication tools and facilities. 相似文献