Development program on a Spindt cold-cathode electron gun

A thin film field emission cathode (TFFEC) array and a cold cathode electron gun based on the emitter were developed. A microwave tube gun that uses the thin film field emission cathode as an electron source is produced. State-of-the-art cathodes were fabricated and tested. The tip-packing density of the arrays were increased thereby increasing the cathode's current density capability. The TFFEC is based on the well known field emission effect and was conceived to exploit the advantages of that phenomenon while minimizing the difficulties associated with conventional field emission structures, e.g. limited life and high voltage requirements. Field emission follows the Fowler-Nordheim equation

Electrophoretic deposition of ferrite

The ability to integrate a material with a high permeability on chip, allows for magnetically coupled circuits and structures to be designed and incorporated along side CMOS circuitry. Devices ranging from A.C. transformers to magnetically driven MEMS structures can be designed and fabricated. Desirable characteristics of magnetic cores for integrated inductors and transformers are first high saturation flux in order to obtain high saturation current; high permeability to obtain high inductance; high resistivity to reduce eddy current loss at high frequencies and compatible deposition and patterning processes. High frequency magnetic materials are oxide based ceramics and are therefore difficult to evaporate, sputter, plate and selectively etched. ElectroPhoretic Deposition (EPD) is a method where insulating particles are imparted charge in a suspension and are made to deposit on an electrode by applying electric field. EPD has been extensively employed in depositing oxide based phosphors for display applications. In this study, ferrite particles have been prepared by grinding sintered toroids and deposited by EPD. The electrophoretic solution bath is composed of isopropyl alcohol with traces of Mg(N03)2 and La(N03)3 salts. Glycerol is added to the solution bath as a surfactant to promote increased substrate adhesion. The dissociation of magnesium nitrate in the solution bath charges the ferrite particles. An electric field of ~ 50-160 V/cm is applied with negative terminal connected to the wafer to be plated and aluminum electrode is used as the anode. The deposition process is found to be self limiting with the initial high elerophoretic current declining to 10% of its value in 10 minutes. The deposition rate and zeta potential measurements indicate a high particle velocity on the order 5.7x10-3 cm/s with an electric field of 160V/cm generated across the 2 cm electrode spacing. Pattern filling and conformal coverage in copper damascene planar microinductors has been investigated. A method to extracted permeability from S11 impedance analysis has been employed. It has been found that grinding process deteriorates magnetic response. With recent advances in magnetic particle technology for high frequency materials, these results enable unique hard and soft powder ferrite material to be selectively deposited in wide variety of CMOS and MEM’s based applications

Suspended SU-8 structures for monolithic microfluidic channels

SU-8 photoresist is commonly used in the field of microfabrication as structural material or for molding of microfluidic devices. One major limitation, however, is the difficulty to process partially freestanding SU-8 structures or monolithic closed cavities and channels on-chip. We propose here a simple method for the fabrication of suspended structures, in particular of monolithic SU-8 microchannels. The method is based on the processing of a SU-8 double-layer. Appropriate modification of the optical properties of the upper layer allows for selective crosslinking in the layer sandwich. This process is suitable for versatile layouts comprising open and hollow SU-8 structures on the same chi

Linear laser diode arrays for improvement in optical disk recording for space stations

The design and fabrication of individually addressable laser diode arrays for high performance magneto-optic recording systems are presented. Ten diode arrays with 30 mW cW light output, linear light vs. current characteristics and single longitudinal mode spectrum were fabricated using channel substrate planar (CSP) structures. Preliminary results on the inverse CSP structure, whose fabrication is less critically dependent on device parameters than the CSP, are also presented. The impact of systems parameters and requirements, in particular, the effect of feedback on laser design is assessed, and techniques to reduce feedback or minimize its effect on systems performance, including mode-stabilized structures, are evaluated

Patterned Nanomagnetic Films

Nano-fabrication technologies for realising patterned structures from thin films are reviewed. A classification is made to divide the patterning technologies in two groups namely with and without the use of masks. The more traditional methods as well as a few new methods are discussed al in relation with the application. As mask less methods we discussed direct patterning with ions including FIB, nanopaterning with electron beams, interferometric laser annealing and ion beam induced chemical vapour deposition. The methods using masks are ion irradiation and projection, interference lithography, the use of pre-etched substrates and templates from diblock copolymers and imprint technologies. First a few remarks are given about the magnetic properties of patterned films but the main part of this paper is focussed on the various patterning technologies. Finally two important applications are summarized such as media for ultra high-density recording and magnetic logic devices. Nanometer scale magnetic entities (nanoelements, nanodots, nanomagnets) form a fast growing new area of solid-state physics including the new fields of applications

The fabrication of micro- and nano- scale deterministic and stochastic pillar arrays for planar separations

Planar chromatography, unlike high performance liquid chromatography (HPLC), has not experienced a significant evolution in stationary phase media since the development of the technique. This has lead HPLC to become a much more popular and robust analytical method. Main factors that contribute to improved performance of chromatographic systems include a reduction in particle size, homogeneity of the stationary phase, and an increase in velocity of the mobile phase. In general, a reduction in particle size should lead to an improvement in the performance of all chromatography systems. However, the main obstacle of improving the performance of planar chromatography systems is that a reduction in particle size leads to a reduction in the capillary flow that governs solvent velocity. This decrease in solvent velocity leads to band broadening resulting in poor efficiency and resolution which are critical performance parameters for chromatographic systems. The research presented herein investigates the scaling down of dimensions to the micro- and nano-scale for pillar arrays in order to investigate the effect on plate height and chromatographic efficiency of these capillary action driven micro- and nano-fluidic systems. Sample application is a critical parameter that effects band broadening in UTLC systems. By taking advantage of the superhydrophobic nature of these arrays the development of a spotting method that demonstrates the ability to create reproducible sample spots that are less than 200 microns (micro- scale arrays) and 400nm (nano- scale arrays) within these arrays are highlighted in this dissertation. We have demonstrated the fabrication of deterministic micro-scale arrays that exhibit plate heights as low as 2µm as well as deterministic and stochastic nanothin-layer chromatographic platforms. Most significantly these systems resulted in bands that were highly efficient, with plate heights in the nm range. This resulted in significant separations of analytical laser test dyes, environmentally significant NBD-derivatized amines, and, biologically relevant chemotherapy drugs (Adriamycin and Daunorubicin)

Flat-plate solar array project. Volume 5: Process development

The goal of the Process Development Area, as part of the Flat-Plate Solar Array (FSA) Project, was to develop and demonstrate solar cell fabrication and module assembly process technologies required to meet the cost, lifetime, production capacity, and performance goals of the FSA Project. R&D efforts expended by Government, Industry, and Universities in developing processes capable of meeting the projects goals during volume production conditions are summarized. The cost goals allocated for processing were demonstrated by small volume quantities that were extrapolated by cost analysis to large volume production. To provide proper focus and coverage of the process development effort, four separate technology sections are discussed: surface preparation, junction formation, metallization, and module assembly