University of California

Ronald G Musket

Robert J Contolini

Jeffrey D Morse

John D Porter

Anthony F Bernhardt

Thomas E Felter

Robert G Patterson

James M Yoshiyama

An improved Faraday cup array for determining the dose of ions delivered to a substrate during ion implantation and for monitoring the uniformity of the dose delivered to the substrate. The improved Faraday cup array incorporates a variable size ion beam aperture by changing only an insertable plate that defines the aperture without changing the position of the Faraday cups which are positioned for the operation of the largest ion beam aperture. The design enables the dose sensitivity range, typically 10  ions/cm to be extended to below 10 ions/cm . The insertable plate/aperture arrangement is structurally simple and enables scaling to aperture areas between <1 cm and >750 cm , and enables ultra-high vacuum (UHV) applications by incorporation of UHV-compatible materials.

Versatile, high-sensitivity faraday cup array for ion implanters

Nanometer-size wires having a cross-sectional dimension of less than 8 nm with controllable lengths and diameters are produced by infiltrating latent nuclear or ion tracks formed in trackable materials with atomic species. The trackable materials and atomic species are essentially insoluble in each other, thus the wires are formed by thermally driven, self-assembly of the atomic species during annealing, or re-crystallization, of the damage in the latent tracks. Unlike conventional ion track lithography, the inventive method does not require etching of the latent tracks.

Formation of nanometer-size wires using infiltration into latent nuclear tracks

A process for fabricating a nanofilament field emission device. The process enables the formation of high aspect ratio, electroplated nanofilament structure devices for field emission displays wherein a via is formed in a dielectric layer and is self-aligned to a via in the gate metal structure on top of the dielectric layer. The desired diameter of the via in the dielectric layer is on the order of 50-200 nm, with an aspect ratio of 5-10. In one embodiment, after forming the via in the dielectric layer, the gate metal is passivated, after which a plating enhancement layer is deposited in the bottom of the via, where necessary. The nanofilament is then electroplated in the via, followed by removal of the gate passification layer, etch back of the dielectric, and sharpening of the nanofilament. A hard mask layer may be deposited on top of the gate metal and removed following electroplating of the nanofilament.

Formation of nanofilament field emission devices

A process involving vapor etching of nuclear tracks in dielectric materials for creating high aspect ratio (i.e., length much greater than diameter), isolated cylindrical holes in dielectric materials that have been exposed to high-energy atomic particles. The process includes cleaning the surface of the tracked material and exposing the cleaned surface to a vapor of a suitable etchant. Independent control of the temperatures of the vapor and the tracked materials provide the means to vary separately the etch rates for the latent track region and the non-tracked material. As a rule, the tracked regions etch at a greater rate than the non-tracked regions. In addition, the vapor-etched holes can be enlarged and smoothed by subsequent dipping in a liquid etchant. The 20-1000 nm diameter holes resulting from the vapor etching process can be useful as molds for electroplating nanometer-sized filaments, etching gate cavities for deposition of nano-cones, developing high-aspect ratio holes in trackable resists, and as filters for a variety of molecular-sized particles in virtually any liquid or gas by selecting the dielectric material that is compatible with the liquid or gas of interest.

Vapor etching of nuclear tracks in dielectric materials

A process for sharpening arrays of field emitter tips of field emission cathodes, such as found in field-emission, flat-panel video displays. The process uses sputtering by high-energy (more than 30 keV) ions incident along or near the longitudinal axis of the field emitter to sharpen the emitter with a taper from the tip or top of the emitter down to the shank of the emitter. The process is particularly applicable to sharpening tips of emitters having cylindrical or similar (e.g., pyramidal) symmetry. The process will sharpen tips down to radii of less than 12 nm with an included angle of about 20 degrees. Because the ions are incident along or near the longitudinal axis of each emitter, the tips of gated arrays can be sharpened by high-energy ion beams rastered over the arrays using standard ion implantation equipment. While the process is particularly applicable for sharpening of arrays of field emitters in field-emission flat-panel displays, it can be effectively utilized in the fabrication of other vacuum microelectronic devices that rely on field emission of electrons.

Growing community of inventors

Danville, CA, United States of America

Ronald G Musket