Skip to main content

Electronics

Latest Innovations
Metal-Assisted Etching for Improved Porous Semiconductors The invention is a novel method for manufacturing porous semiconductors, including silicon (Si), gallium nitride (GaN) and silicon carbide (SiC). The method... Read More The invention is a novel method for manufacturing porous semiconductors, including silicon (Si), gallium nitride (GaN) and silicon carbide (SiC). The method involves applying a thin, discontinuous metallic (preferably platinum) layer to a semiconductor wafer, prior to using common wet chemical etchants (e.g., hydrogen fluoride, hydrogen peroxide), to produce porous silicon (PSi) or other porous semiconductors (PGaN, PSiC). Porous semiconductors are of interest for their novel optical, electronic, and chemical properties, with PSi being of particular interest. This technology applies a thin, discontinuous layer of metal to a semiconductor wafer before using a wet chemical etching process to produce a controlled thickness of porous semiconductor. The process can be adjusted to produce specific morphologies and desired light emission spectral and/or spatial distributions. This technology introduces a thin, metal catalyst film (a few nanometers in thickness) onto the semiconductor wafer surface, prior to immersion in an aqueous, oxidizing solution of hydrofluoric acid and hydrogen peroxide (i.e., H2O2 metal-HF etching). This process results in the simple and effective production of porous semiconductor. The simplicity and patterning capability will enable large-scale production. PSi with various morphologies, etch depths, and luminescent properties can be produced by adjusting the type(s) of metal layer deposited (gold, platinum, or gold/palladium) as well as the dopant type and level (p+, p-, or n+) of the silicon. Current methods for generating PSi use anodic etching. In anodic etching, a silicon wafer with attached electrodes and leads is submerged in a wet chemical bath and an electrical bias is applied to drive the etching process. While PSi is not commonly used today in optical or electrical devices, anodic etching is used routinely to generate PSi used to fabricate silicon-on-insulator (SOI) wafers for the electronics industry. A drawback of anodic etching is the extra infrastructure and complexity of applying an electrical bias to a thin wafer submerged in an etchant. At a minimum, it requires electrodes, leads, a power supply, and control electronics. This new technology is an elegantly simple alternative to anodic etching. It is an electroless technique, i.e., external electrical bias is not required, that circumvents all electrical accessories and associated methods. This novel process is also robust, controllable, and even allows flexibility for generating PSi in selected areas rather than across the entire wafer. In addition, this technology provides up to an order of magnitude enhancement in the luminescent properties of PSi compared to those of material produced using anodic etching. Furthermore, researchers may find applications for PSi that would never be possible using anodic etching. Applications: Light-emitting diodes (LEDs) Chemical/Biological sensors Compliant substrates for heteroepitaxial growth (e.g., nitrides) Sacrificial layers for microelectromechanical devices Low-dielectric interconnects Benefits: Enhanced Control over Product Properties: Both the morphology and light-emitting properties (spatial profile, wavelength) of the semiconductor can be tailored as a function of metal deposited, semiconductor doping level, semi-doping type, and etch time. Simple and Robust Process: By using metal deposition and etching, both simple, accepted processes in microelectronics, this "contactless" technology does not require the presence of electrical contacts or other stimuli/equipment to control etching. Directed Area Etching/Luminescence: Selective deposition or patterning of the metal catalyst allows controlled creation of etch variations in substrates below and adjacent to the metal. This method can also create selected areas with unique emission properties. Promising Potential Properties: This technology might lead to in situ contacts for porous semiconductors/silicon; have potential for ten-fold better luminescent emission from PSi than that obtained from anodic etching; enhance the emission of other semiconductors beyond silicon (e.g., GaN) or enable compliant substrates for heteroepitaxy; and enable creation of PSi on a variety of substrate shapes and sizes.
Aligned Free-Standing Copper Nanowires This invention fabricates copper nanowires using thermal chemical vapor deposition (CVD) at temperatures of about 200 to 400 C. The method can produce vertically... Read More This invention fabricates copper nanowires using thermal chemical vapor deposition (CVD) at temperatures of about 200 to 400 C. The method can produce vertically aligned copper nanowires on various metallic, oxide, and plastic substrates without the need for pores, templates, catalysts, or lithography of the substrate surface. The CVD process does not use hydrogen and is compatible with standard silicon processing technologies. Copper wires with diameters of 70 to100 nanometers and lengths of several microns can be produced and characterized. Electron emission properties have been measured and are superior to most other materials including carbon nanotubes. The processing conditions are adjusted so as to promote the growth of wires instead of films. Applications: Flat panel display devices Computing Medical imaging Entertainment Home appliances Wireless communication Remote sensors Benefits: Simplicity and scalability - A straightforward CVD process that uses standard equipment is utilized. This technique does not require complex substrate preparation. Compatibility - The process is compatible with most standard semiconductor processing protocols. The wires can be grown on a wide variety of materials including metals, silicon, and plastics.
Ohmic & Gate Contacts for High Electron Mobility Transistors (HEMTs) Ohmic contact degradation and gate-sinking are two major degradation mechanisms that cause semiconductor devices, such as high electron mobility transistors, or... Read More Ohmic contact degradation and gate-sinking are two major degradation mechanisms that cause semiconductor devices, such as high electron mobility transistors, or HEMTs, to fail. In general, the rapid diffusion of contact metals into the indium phosphide substrates has restricted processing temperatures to 300C and reliable operating temperatures have been limited to 200C to 250C. This set of technologies embodies two similar methods for improving reliability and performance of contacts in indium phosphide-based semiconductors. Both alleviate the diffusion of metals into the semiconductor substrate, and the resulting impairment of device performance, by changing the composition of the metal contacts. For the first time, enhancement mode high electron mobility transistors (e-HEMTs) are practical in these material systems. Details By substituting a new metallization scheme in ohmic contacts, and an iridium-based metallization for gate contacts, processing can take place at temperatures greater than 400C, offering a processing temperature window 100C to 150C wider than was available previously. Diffusion of the metal into the substrate is reduced, thereby increasing reliability and operating lifetime. In addition, with the increased Schottky barrier height offered by the use of the new gate metallization, a true reliable indium phosphide enhancement mode HEMT, or e-HEMT, is now possible. An e-HEMT draws no power in its "off" state, a significant benefit in mobile communications applications. Applications Wireless communications Satellite communications Defense applications High-frequency devices Benefits Higher temperature annealing Reduced diffusion of contact metal into substrate Higher reliability Higher temperature operation possible Enables true enhancement-mode high electron mobility transistors
Autonomous Self-Regulating Microfluidic System This technology enables the fabrication of microfluidic devices that automatically maintain homeostasis via an organic feedback system. Originally developed to... Read More This technology enables the fabrication of microfluidic devices that automatically maintain homeostasis via an organic feedback system. Originally developed to create self-regulating pH systems, this technology can be used to create medical/biological devices that self-govern temperature, light, molecular, and other fluid parameters. Most microfluidic devices designed to maintain homeostasis use feedback systems based on electronics or other non-biologically compatible actuation methods. To overcome the limitations of those devices, this technology uses a responsive polymeric material hydrogel as the control system. According to its chemistry, the hydrogel expands when exposed to a given condition (e.g., high pH) and constricts in the opposite condition (e.g., low pH). As the hydrogel expands and contracts, it deforms a 30 m polydimethylsiloxane membrane that regulates the feedback stream. The hydrogel's chemistry is selected according to the fluid parameter of interest. In this way, the microfluidic device operates without electronics or external power, allowing it to be used in medical and biological applications. Construction of the device, which involves compression micromolding, layered manufacturing, and in situ liquid phase polymerization, can be completed in one day and is less expensive than other manufacturing techniques for microfluidic systems. Advantages These new technologies enable the fabrication of innovative microfluidic devices that address many of the limitations associated with conventional systems: Unlike silicon-based devices, the new device is easy to incorporate into medical and biological applications. Unlike devices made from a single material (e.g., elastomer-only devices), the new device is capable of performing complex functions. Unlike all other devices, the new self-regulating device functions autonomously without electronics or an external power source. Unlike traditional microfabrication methods, this technology uses inexpensive methods to produce increased functionality. Unlike devices that use expensive microchips in the channels, the new microfluidic device uses surface chemistry to expand its functionality. In summary, the technology enables the economical, simple, and rapid fabrication of more functionally complex microfluidic devices than are available today. Applications Clinical medicine: Artificial lung, responsive drug (e.g., insulin) delivery, feedback control devices Bioproduction: Protein production, assisted reproduction, filtration Research: Incubation/maturation, infection, fertilization, chemical or other treatment of biological objects, reaction kinetics, high surface area sensing substrates, feedback control, drug candidate solubility Bioanalysis: DNA analysis, sequence determination of proteins Benefits This technology dramatically expands the capabilities of microfluidic devices. It enables the economical, simple, and rapid fabrication of more functionally complex systems than are available today. Simple: This technology greatly simplifies the fabrication process for microfluidic devices. Less expensive: This technology uses less expensive materials and fabrication methods than those conventionally used to manufacture microfluidic devices. Fast: This technology enables microfluidic devices to be constructed in minutes, as compared to days or weeks with more traditional fabrication methods. Better devices: Microfluidic devices made using this technology have enhanced capabilities compared to those made with traditional fabrication methods: Greater functionality Autonomous operation; no external power supply or electronics are needed Flexible design that is useful for medical and biological applications
Thin Film Wafer Bonding Amorphous and polycrystalline III-V semiconductor including (Ga,As), (Al,As), (In,As), (Ga,N), and (Ga,P) materials were grown at low temperatures on semiconductor... Read More Amorphous and polycrystalline III-V semiconductor including (Ga,As), (Al,As), (In,As), (Ga,N), and (Ga,P) materials were grown at low temperatures on semiconductor substrates. After growth, different substrates containing the low temperature grown material were pressed together in a pressure jig before being annealed. The annealing temperatures ranged from about 300.degree. C. to 800.degree. C. for annealing times between 30 minutes and 10 hours, depending on the bonding materials. The structures remained pressed together throughout the course of the annealing. Strong bonds were obtained for bonding layers between different substrates that were as thin as 3 nm and as thick as 600 nm. The bonds were ohmic with a relatively small resistance, optically transparent, and independent of the orientation of the underlying structures.
Improvements for electically assisted chemical oxygen-iodine laser In one embodiment of the present invention an oxygen iodine laser includes a gas mixing section. Ground state oxygen and a carrier gas are introduced into the... Read More In one embodiment of the present invention an oxygen iodine laser includes a gas mixing section. Ground state oxygen and a carrier gas are introduced into the first gas mixing section, sometimes separately. The laser includes a discharge region to generate at least said excited oxygen from the flow of the first gas mixing section. A sensitizer gas having a lower ionization threshold than ground state oxygen is also introduced into the first gas mixing section, such that electrons are more easily produced in the electrical generator. The laser system includes introducing a source of iodine into the excited singlet delta oxygen flow to generate a laser-active gas. In another embodiment a conditioner is placed into the gas mixing section to help mix the flow and/or introduce one or more of the aforementioned gases.
Crosslinked, Conjugated Carbon Monolayers This technology is a method of making monolayer carbon films. Read More This technology is a method of making monolayer carbon films.
Optical Frequency Up-Conversion of Femtosecond Pulses into Targeted Single Bands in the Visible and Ultraviolet An apparatus and methods for generating a substantially supercontinuum-free widely-tunable multimilliwatt source of radiation characterized by a narrowband line profile.... Read More An apparatus and methods for generating a substantially supercontinuum-free widely-tunable multimilliwatt source of radiation characterized by a narrowband line profile. The apparatus and methods employ nonlinear optical mechanisms in a nonlinear photonic crystal fiber (PCF) by detuning the wavelength of a pump laser to a significant extent relative to the zero-dispersion wavelength (ZDW) of the PCF. Optical phenomena employed for the selective up-conversion in the PCF include, but are not limited to, four-wave mixing and Cherenkov radiation. Tunability is achieved by varying pump wavelength and power and by substituting different types of PCFs characterized by specified dispersion properties. Optical frequency up-conversion of infrared (850-1100nm) femtosecond laser pulses into visible pulses (470-690nm) by Cherenkov radiation and inter-modal four-wave mixing in photonic crystal fibers (PCF) enables generation of: multi-milliwatt tunable supercontinuum-free optical pulses in a wavelength region otherwise inaccessible from the source. Current commercial devices for optical frequency up-conversion are optical parametric amplifiers based on Four-wave mixing (FWM). These devices are input laser wavelength specific, expensive and usually have a large footprint. Whereas other similar devices require dedicated fabrication facilities or special components, frequency up-conversion based on Cherenkov radiation does not call for exotic dispersion engineering of the photonic crystal fiber. The resulting compact device can be used with source lasers with various wavelengths. Intense, clean visible pulses have potential application in ultrafast spectroscopy, coherent nonlinear spectroscopy and multi-photon microscopy. Screen Shot 2016-09-16 at 1.51.58 PM.png
Blue-Shifting Of Resonant Dispersive Wave Pulses Researchers from the University of Illinois have developed a way to shift a laser beam into a broadband of light with lower wavelengths. This technology enables... Read More Researchers from the University of Illinois have developed a way to shift a laser beam into a broadband of light with lower wavelengths. This technology enables the use of pulsed pump lasers in ultrafast spectroscopy, nonlinear biomedical imaging, and many other imaging fields.
Efficient Detection of Peroxide-Based Explosives TATP (triacetone triperoxide) has emerged as an explosive of choice for terrorists in recent years, because it is easy to produce, highly explosive, and hard to... Read More TATP (triacetone triperoxide) has emerged as an explosive of choice for terrorists in recent years, because it is easy to produce, highly explosive, and hard to detect. Some recent examples of TATP use are the Northwest Airlines Flight 253 attempted bombing (2009), the London bombings (2005), and the American Airlines Flight 63 attempted bombing (2001). Because TATP and other peroxide-based explosives lack UV absorbance, fluorescence, or facile ionization, typical methods of detecting explosives do not work to detect TATP. The current methods of detecting TATP additionally have many drawbacks, such as being limited to detecting TATP in only the liquid or solid phases or requiring complicated sample processing or expensive instrumentation. This technology provides an efficient, handheld method of detecting TATP and other peroxide-based explosives in the vapor phase. The technology is resistant to potential interferences, such as humidity, personal hygiene products, perfume, etc. It can be easily implemented at security checkpoints or wherever else TATP detection is required. Details This technology uses a handheld unit with replaceable cartridges to sniff out trace amounts of peroxide-based explosives in the vapor phase. The unit is held near a person or item to be screened and allowed to take in a sampling of the air in the immediate vicinity. The air sample is then analyzed for the presence of peroxide-based explosives. The handheld unit can provide a semi-quantitative analysis of TATP concentrations from 50 ppb to 10 ppm, though it can detect the presence of TATP in concentrations as low as 2 ppb (less than 0.02% of its saturation vapor pressure). Applications Airport security Customs & Border Patrol Military Concerts Sporting events Political events Building security Benefits Portable (handheld device) Capable of detecting TATP in the gas phase in concentrations as low as 2 ppb (less than 0.02% of its saturation vapor pressure) Allows semi-quantitative analysis from 50 ppb to 10 ppm Works in the presence of potential interferences (humidity, personal hygiene products, perfume, etc.) Can differentiate TATP from other oxidants (hydrogen peroxide, bleach, etc.)

Pages