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June 2001

The Laboratory
in the News

Commentary by
Lee Younker

Turning Carbon
Directly into

Research in State
and Beyond

This Nitrogen
Molecule Really
Packs Heat

Goes to Work






Steven Falabella
Amorphous-Diamond Electron Emitter
U.S. Patent No. 6,204,595 B1
March 20, 2001
An electron emitter comprising a textured silicon wafer overcoated with a thin (200-nanometer) layer of nitrogen-doped, amorphous diamond, which lowers the field below 20 volts per micrometer, compared to uncoated or diamond-coated emitters wherein the emission is at fields of nearly 60 volts per micrometer. The silicon/nitrogen-doped, amorphous-diamond (Si/a:D-N) emitter may be produced by overcoating a textured silicon wafer with amorphous diamond in a nitrogen atmosphere using a filtered cathodic-arc system. The enhanced performance of the Si/a:D-N emitter lowers the voltages required to the point where field-emission displays are practical. Thus, this emitter can be used, for example, in flat-panel emission displays and cold-cathode vacuum electronics.

Harold D. Ackler, Stefan P. Swierkowski, Lisa A. Tarte, Randall K. Hicks
Method for Vacuum Fusion Bonding
U.S. Patent No. 6,205,819 B1
March 27, 2001
An improved vacuum fusion bonding structure and process for aligned bonding of large-area glass plates, patterned with microchannels and access holds and slots, for elevated glass fusion temperatures. Vacuum pumpout of all components is through the bottom platform, which yields an untouched, defect-free top surface that greatly improves optical access through its smooth surface. Also, a completely nonadherent layer, such as graphite, that has alignment and location features, is located between the main steel platform and the glass plate pair. This nonadherent layer makes large improvements in quality, yield, and ease of use, and enables aligned bonding of very large glass structures.

Layton C. Hale, Terry N. Malsbury, Steven R. Patterson
Pedestal Substrate for Coated Optics
U.S. Patent No. 6,206,966 B1
March 27, 2001
A pedestal optical substrate that simultaneously provides high substrate dynamic stiffness, provides low surface figure sensitivity to mechanical mounting hardware inputs, and constrains surface figure changes caused by optical coatings to be primarily spherical in nature. The pedestal optical substrate includes a disklike optic or substrate section having a top surface that is coated, a disklike base section on which the substrate can be mounted, and a connecting cylindrical section between the base and optics or substrate sections. The connecting cylindrical section may be attached via three spaced legs or members. However, the pedestal optical substrate can be manufactured from a solid piece of material to form a monolith, thus avoiding joints between the sections, or the disklike base can be formed separately and connected to the connecting section. The pedestal optical substrate may be used in the fabrication of optics for an extreme ultraviolet lithography imaging system or in any optical system requiring coated optics and substrates with reduced sensitivity to mechanical mounts.

Judith E. Kammeraad, Jerome J. Blair
System to Quantify Gamma-Ray Radial Energy Deposition in Semiconductor Detectors
U.S. Patent No. 6,207,957 B1
March 27, 2001
A system for measuring gamma-ray radial energy deposition is provided for use in conjunction with a semiconductor detector. The detector comprises two electrodes and a detector material; it defines a plurality of zones within the detecting material in parallel with the two electrodes. The detector produces a charge signal E(t) when a gamma ray interacts with the detector. Digitizing means are provided for converting the charge signal E(t) into a digitized signal. A computational means receives the digitized signal and calculates which of the plurality of zones the gamma-ray deposited energy is in when interacting with the detector. The computational means produces an output indicating the amount of energy deposited by the gamma ray in each of the plurality of zones.

William J. Benett, Peter A. Krulevitch
Microfluidic Interconnects
U.S. Patent No. 6,209,928 B1
April 3, 2001
A miniature connector for introducing microliter quantities of solutions into microfabricated fluidic devices. The fluidic connector, for example, joins standard high-pressure liquid chromatography tubing to 1-millimeter-diameter holes in silicon or glass, enabling milliliter-sized volumes of sample solutions to be merged with microliter-sized devices. The connector has many features, including ease of connection and disconnection, a small footprint that enables numerous connectors to be located in a small area, low dead volume; helium leakproofness, and tubing that does not twist during connection. Thus, the connector enables easy and effective change of microfluidic devices and introduction of different solutions in the devices.

John C. Whitehead
Fluid Intensifier Having a Double-Acting Power Chamber with Interconnected Signal Rods
U.S. Patent No. 6,210,131 B1
April 3, 2001
A fluid-driven reciprocating apparatus having a double-acting power chamber with signal rods serving as high-pressure pistons, or to transmit mechanical power. The signal rods are connected to a double-acting piston in the power chamber, thereby eliminating the need for pilot valves, with the piston being controlled by a pair of intake exhaust valves. The signal rod includes two spaced seals along its length with a vented space there or in between so that the driving fluid and driven fluid cannot mix; the rod performs a switching function to eliminate separate pilot valves. The intake–exhaust valves can be integrated into a single housing with the power chamber, or these valves can be built into the cylinder head only of the power chamber, or they can be separate from the power chamber.

Stephen A. Payne, Christopher D. Marshall, Howard T. Powell, William F. Krupke
Hybrid Solid State Laser System Using a Neodymium-Based Master Oscillator and an Ytterbium-Based Power Amplifier
U.S. Patent No. 6,212,215 B1
April 3, 2001
In a master oscillator–power amplifier (MOPA) hybrid laser system, the master oscillator (MO) utilizes a Nd3+-doped gain medium and the power amplifier (PA) utilizes a diode-pumped Yb3+-doped material. The use of two different laser gain media in the hybrid MOPA system provides advantages that are otherwise not available. The Nd-doped gain medium preferably serves as the MO because such gain media offer the lowest threshold of operation and have already been engineered as practical systems. The Yb-doped gain medium preferably serves in the diode-pumped PA to store pump energy effectively and efficiently by virtue of the long emission lifetime, thereby reducing diode pump costs. One crucial constraint on the MO and PA gain media is that the Nd and Yb lasers must operate at nearly the same wavelength. The 1,047-micrometer Nd:YLF/Yb:S-FAP [Nd:LiYF4/Yb:Sr5(PO4)3F] hybrid MOPA system is a preferred embodiment of the hybrid Nd/Yb MOPA.

Walt W. McNab, Jr., Robert Ruiz, Tristan M. Pico
Situ Treatment of Contaminated Groundwater
U.S. Patent 6,214,202, B1
April 10, 2001
A system for treating dissolved halogenated organic compounds in groundwater that relies on electrolytically generated hydrogen to chemically reduce the halogenated compounds in the presence of a suitable catalyst. A direct current is placed across at least a pair or an array of electrodes housed within groundwater wells so that hydrogen is generated at the cathode and oxygen at the anode. A pump is located within the well housing in which the cathode(s) is(are) located and draws in groundwater where it is hydrogenated by electrolysis, passes through a well-bore treatment unit, and is then transported to the anode well(s) for reinjection into the ground. The well-bore treatment involves a permeable cylinder located in the well bore. The cylinder contains a packed bed of catalyst material that facilitates the reductive dehalogenation of the halogenated organic compounds by hydrogen into environmentally benign species such as ethane and methane. Also, electrosomatic transport of contaminants toward the cathode also contributes to contaminant mass removal. The only aboveground equipment required is the transfer pipes and a direct circuit power supply for the electrodes. The electrode wells in an array may be used in pairs, or one anode well may be used with a plurality of cathode wells. The direct current flow between electrode wells may be periodically reversed to control the formation of mineral deposits in the alkaline cathode well-bore water as well as to help rejuvenate the catalysis.

Alan F. Jankowski, Anthony P. Schmid
Process for Producing Ti–Cr–Al–O Thin Film Resistors
U.S Patent 6,217,722 B1
April 17, 2001
Thin films made of titanium–chromium–aluminum–oxygen (Ti–Cr–Al–O) are used as a resistor material. The films are radiofrequency-sputter deposited from ceramic targets using a reactive working gas mixture of argon and oxygen. Resistivity values of 104 to 1010 ohm-centimeters have been measured for Ti–Cr–Al–O film less than 1 micrometer thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. Ti–Cr–Al–O thin films, unlike other metal oxide films, have been found to be thermodynamically stable when applied as a thin-film resistor. The Ti–Cr–Al–O film can be used as a vertical or lateral resistor (for example, as a layer beneath a field emission cathode in a flat-panel display), or it can be used to control surface emissivity (for example, as a coating on an insulating material such as vertical wall supports in flat-panel displays).

Kurt H. Weiner
Process for Fabricating Device Structures for Real-Time Process Control of Silicon Doping
U.S. Patent 6,221,726 B1
April 24, 2001
Silicon device structures designed to allow measurement of important doping process parameters immediately after the doping step has occurred. The test structures are processed through contact formation using standard semiconductor fabrication techniques. After the contacts have been formed, the structures are covered by an oxide layer and an aluminum layer. The aluminum layer is then patterned to expose the contact pads and selected regions of the silicon to be doped. Doping is then performed, and the whole structure is annealed with a pulsed excimer laser. But laser annealing, unlike standard annealing techniques, does not affect the aluminum contacts because the laser light is reflected by the aluminum. Once the annealing process is complete, the structures can be probed using standard techniques to ascertain data about the doping step. Analysis of the data can determine probable yield reductions due to improper execution of the doping step and thus provides real-time feedback during integrated circuit fabrication.

Raymond J. Beach, Eric C. Honea, Stephen A. Payne
Delivering Pump Light to a Laser Gain Element While Maintaining Access to the Laser Beam
U.S. Patent 6,222,872 B1
April 24, 2001
A lens duct is used to pump delivery, and the laser beam is accessed through an additional component called the intermediate beam extractor that can be implemented as part of the gain element or the lens duct or as a separate component.

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UCRL-52000-01-6 | July 23, 2001