recent trends in biosensors

for determination of organic compounds in foods, electrochemical monitoring devices (biosensors) employing immobilized biocatalysts such as immobilized enzymes, organelles, microorganisms and tissue have definite advantages. enzyme sensors could be used for the determination of sugars, amino acids, organic acids, alcohols, lipids, nucleic..

two layer planarization process

a two layer planarization (tlp) process has been developed to solve the profile variation problems encountered in conventional planarization. all the topographic features are smoothed down regardless of their size and spacing. the tpl process involves a first positive photoresist layer spun onto the substrate and exposed through a negativ..

effect of irradiation on immobilized enzymes compared with that on enzymes in solution

glucose oxidase and catalase were immobilized by attaching them to nylon fibers that had been treated with triethyloxonium-tetrafluoroborate, diaminohexane and glutardialdehyde according to morris, campbell and hornby (1975) this method assures that the enzymes are bound to a side chain of the polyamide structure. enzyme activity (as meas..

mosfet fabrication using ion beam nitridation

ion beam nitridation has been suggested as an alternative to the conventional local oxidation process which is used in the fabrication of most metal-oxide-semiconductor (mos) integrated circuits. the implantation of 2 kev nitrogen ions in doses of up to 8*10/sup 17/ cm/sup -2/ results in the formation of a silicon nitride layer approximat..

chemicals play vital roles in pcb manufacturing

from etching and plating to cleaning and joining, chemicals play a vital role in the fabrication and assembly of printed circuit boards. the chemicals may be grouped into the following categories' substrates, image-producing materials, wet chemicals, plating chemicals, gases and packaging materials. to these, cleaning, joining and bonding..

magnetic separators for cleaning of kaolin at the zkz plant in horni briza

two types of magnetic devices for sorting and cleaning of materials in the fabrication of ceramic and porcelain products are described based on resistive and superconducting principle, respectively. the resistance separator employs a rotationally symmetrical magnetic circuit with series connected coils and a three-phase bridge solid-state..

etching and surface preparation of gaas for device fabrication

a complete gaas device fabrication process may involve epitaxial growth, ion implantation, lithography, metallizations, alloying and annealing steps, as well as a number of etching and surface preparation steps. in fabricating lateral devices, etching is used for mesa isolating a device (although ion beam isolation is also available) and ..

a mechanism for induced surface degradation of high-resistive gaas during device fabrication

undoped, liquid-encapsulated-czochralski (lec)-grown, semi-insulating (si) gaas crystals were electrically characterized by temperature-dependent hall effect and conductivity measurements to establish the mechanism for thermally induced surface degradation. x-ray photoelectron spectroscopy (xps) was used to obtain depth profiles of the ga..

effect of surface treatment on dopant diffusion in polycrystalline silicon capped shallow junction bipolar transistors

the outdiffusion of boron and arsenic was studied as a function of surface treatment prior to polycrystalline silicon (polysilicon) deposition in the fabrication of bipolar transistors secondary ion mass spectrometry and spreading resistance probe analyses were performed to measure boron, arsenic, and concurrent boron-arsenic diffusion af..

adhesion of graphite fibers to epoxy matrices. iii. the effect of hygrothermal exposure

type as1 surface treated graphite fibers and surface treated and 'finished' (as1c) for improved adhesion to epoxy matrices were used. a substantial difference in interfacial shear strength alteration with hygrothermal exposure was detected at all conditions between the surface treated and the surface treated and 'finished' fibers retained..