Abstract: This invention describes a method of controlling light emission from porous silicon and porous silicon devices using ion implantation. The emitted light intensity can be either selectively increased or decreased by suitable processing of the silicon prior to the fabrication of the porous layer. Amorphizing the silicon prior to the fabrication of the porous layer quenches the light emission. Ion implantation with doses below the amorphization level enhances the intensity of the emitted light of the subsequently fabricated porous layer.

Abstract: An etching process allows a selective single-step patterning of silicon devices in a noncorrosive environment. The etching of silicon relies on a maskless laser-assisted technique in a gaseous halocarbon ambient, such as the gaseous chlorofluorocarbons, dichlorodifluoromethane and chloropentafluoroethane. Laser-assisted photothermal chemical etching reactions on silicon occur in these ambients when the incident fluence from an excimer laser at 248 nm exceeds the melt threshold (approximately 0.75 J/cm.sup.2). When incident fluence exceeds the ablation threshold (approximately 2.2 J/cm.sup.2) an undesirable, increased surface roughness is observed. Etch rates as large as approximately 15 angstroms per pulse are attained within predetermined processing windows. This provides a means for thin membrane formation in silicon, rapid etches and processing of packaged devices or partially fabricated dies.

Abstract: A method to decompose chlorofluorocarbons gases (CFCs) enables the conventional disposal of their by-products. It employs photodecomposition of the CFC gas using UV light and a mediating species to allow chemical reactions to occur which form an effluent which is hydrolyzed by conventional methods.

Abstract: An etching process allows a selective single-step patterning of III-V or II-VI semiconductor compound devices such as GaAs and InP or CdS and ZnSe in a noncorrosive environment. The etching relies on a maskless laser-assisted technique in a gaseous chlorofluorocarbon ambient, such as gaseous dichlorodifluoromethane and chloropentafluoroethane. Laser-assisted photothermal chemical etching reactions on the III-V or II-VI semiconductor compounds occur in these ambients when the incident fluence from an excimer laser at 248 nm exceeds the melt threshold. This provides a means for thin membrane formation in III-V or II-VI semiconductor compounds, rapid etches and processing of packaged devices or partially fabricated dies. The reduction in processing steps as compared to conventional wet chemical etches provides improvements in yield, reliability and cost.

Abstract: An etching process allows a selective single-step patterning of silicon devices in a noncorrosive environment. The etching of silicon relies on a maskless laser-assisted technique in a gaseous halocarbon ambient, such as the gaseous chlorofluorocarbons, dichlorodifluoromethane and chloropentafluoroethane. Laser-assisted photothermal chemical etching reactions on silicon occur in these ambients when the incident fluence from an excimer laser at 248 nm exceeds the melt threshold (approximately 0.75 J/cm.sup.2). When incident fluence exceeds the ablation threshold (approximately 2.2 J/cm.sup.2) an undesirable, increased surface roughness is observed. Etch rates as large as approximately 15 angstroms per pulse are attained within predetermined processing windows. This provides a means for thin membrane formation in silicon, rapid etches and processing of packaged devices or partially fabricated dies.

Abstract: A microelectronic photomultiplier device is fabricated by discrete proceds to provide a photocathode-anode and dynode chain arrangement which is analogous in operation to conventional photomultiplier tubes. This microelectronic photomultiplier device provides for low level photon detection and realizes the advantages of high reliability, small size and fast response, plus lower cost, weight and power consumption compared to conventional photomultiplier tubes. In addition, the fabrication on an SOI substrate permits integration of logic and control circuitry with detectors. The insulating substrate also permits the integration of an on-chip high voltage supply and may easily be extended to a plurality of detectors offering improved performance and design flexibility.

Abstract: A method of rapid sample handling in a production environment for laser processing of individual microelectronic die is particularly suited for handling partially fabricated die and die which are susceptible to mechanical and electrostatic damage, such as backside illuminated CCDs requiring backside dopant activation and laser texturing of sidewalls. Securing a die within a modified sample holder provides for electrostatic and mechanical protection during laser processing. Placing the modified die holder onto a feeder base portion that engages a "tractor-feed" translation subsystem protects the die during a translation and positioning of the die below and aligned with a laser processing structure. A window holder is engaged with the die holder to seal the die in a processing chamber and to assure an appropriate pressurizing with a gaseous ambient for a desired processing.

Abstract: A non-contact method to impart a texture to a surface using laser irradian uses an excimer laser to illuminate a sample immersed in a halocarbon ambient thereby initiating a photo/thermal chemical reaction which etches the sample only in the area illuminated with sufficient laser fluence. The resulting etched area can be repetively illuminated and etched to provide a textured surface to reduce extraneous reflections, or for micromachining, decorative texturing and marking. This technique is particularly well suited to improve the performance of backside illuminated CCDs by reducing the background (dark) signal, increase resolution and responsivity uniformity. The technique is compatible with other laser processing procedures and can be implemented with a variety of CCD enhancements such as improved dark current and blue response from laser doping or activation of backside implants.

Abstract: An etching process allows a selective single-step patterning of III-V or VI semiconductor compound devices such as GaAs and InP or CdS and ZnSe in a noncorrosive environment. The etching relies on a maskless laser-assisted technique in a gaseous chlorofluorocarbon ambient, such as gaseous dichlorodifluoromethane and chloropentafluoroethane. Laser-assisted photothermal chemical etching reactions on the III-V or II-VI semiconductor compounds occur in these ambients when the incident fluence from an excimer laser at 248 nm exceeds the melt threshold. This provides a means for thin membrane formation in III-V or II-VI semiconductor compounds, rapid etches and processing of packaged devices or partially fabricated dies. The reduction in processing steps as compared to conventional wet chemical etches provides improvements in yield, reliability and cost.

Abstract: Processing methods transform ferroelectric precursor films into a desired crystalline structure without adversely heating nearby materials and circuitry such as those found associated with lead zirconate titanate films. The thin film sample is placed within an appropriate chamber, where a suitable ambient is in contact with the thin film sample. The ambient may be air, oxygen or any other ambient which is known in the art to be appropriate for annealing ferroelectric materials. In this regard annealing in air can done without the processing chamber. The process for annealing relies upon continuous wave (CW) laser annealing, pulse UV annealing with or without a laser and various combinations of thermal pretreatment and processing to allow solid state diffusion in accordance with parameters appropriate for a particular application. Methods of laser patterning thin film ferroelectrics without adversely damaging adjacent or underlying layers, e.g. electrodes, are also disclosed.

Abstract: A muitilayer microelectronic photomultiplier device is fabricated by disce procedures to provide a photocathodeanode and dynode chain arrangement which is analogous in operation to conventional photomultiplier tubes. This multilayer microelectronic photomultiplier device provides for low level photon detection and realizes the advantages of high reliability, small size and fast response, plus lower cost, weight and power consumption compared to conventional photomultiplier tubes. In addition, the fabrication on an SOI substrate permits integration of logic and control circuitry with detectors. The insulating substrate also permits the integration of an on-chip high voltage supply and may easily be extended to a plurality of detectors with high packing densities due to the inherently stacked geometry offering improved performance and design flexibility.

Abstract: STATEMENT OF GOVERNMENT INTERESTThe invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Abstract: A microelectronic photomultiplier device is fabricated by discrete proceds to provide a photocathode-anode and dynode chain arrangement which is analogous in operation to conventional photomultiplier tubes. This microelectronic photomultiplier device provides for low level photon detection and realizes the advantages of high reliability, small size and fast response, plus lower cost, weight and power consumption compared to conventional photomultiplier tubes. In addition, the fabrication on an SOI substrate permits integration of logic and control circuitry with detectors. The insulating substrate also permits the integration of an on-chip high voltage supply and may easily be extended to a plurality of detectors offering improved performance and design flexibility.

Abstract: A method for fabricating a conformal optical waveguide on a semiconductor bstrate which results in an improved conformal processing method of producing ferroelectic ceramic waveguides that is integratable with conventional electronic and optoelectronic devices. First, a patterning of a desired waveguide configuration is made on a desired semiconductor substrate. A conformal confinement layer is fabricated in the pattern of the desired waveguide configuration on the semiconductor substrate. The conformal confinement layer has an index of refraction. Next, the method calls for a placing of a sol-gel waveguide precursor in the conformal confinement layer. Next the spin casting of a sol-gel waveguide precursor shapes a sol-gel conformal waveguide layer in the conformal confinement layer on the semiconductor substrate.

Abstract: A method for fabricating graded heterojunction electronic devices uses laser melting and recrystallization of layered films to create an epitaxial alloy heterojunction. Layering an appropriately doped polysilicon film over a germanium film that has been deposited upon a base region allows the laser melting and recrystallization thereof to create a graded epitaxial silicon/germanium alloy heterojunction. Other film materials could be selected for other graded heterojunctions. The method provides for sufficient device design flexibility including deeper junction formation and reduces the problems associated with contamination.

Abstract: A non-contact method to impart a texture to a surface using laser irradiation uses an excimer laser to illuminate a sample immersed in a halocarbon ambient thereby initiating a photo/thermal chemical reaction which etches the sample only in the area illuminated with sufficient laser fluence. The resulting etched area can be repetively illuminated and etched to provide a textured surface to reduce extraneous reflections, or for micromachining, decorative texturing and marking. This technique is particularly well suited to improve the performance of backside illuminated CCDs by reducing the background (dark) signal, increase resolution and responsivity uniformity. The technique is compatible with other laser processing procedures and can be implemented with a variety of CCD enhancements such as improved dark current and blue response from laser doping or activation of backside implants.

Abstract: A tapered optical fiber amplifier is designed to provide for long-distance, un-repeatered fiber optic communications. Two single-mode fiber portions are tapered to efficiently intensify and couple an information signal from a laser diode and a pump signal at a shorter wavelength into a fused, tapered single-mode fiber optic coupler. The concentrated information signal and concentrated pump signal are combined via the coupler which is coupled to a several-kilometer length of a relatively small core diametered single-mode fiber to create a nonlinear optical effect (stimulated Raman scattering) (SRS). The SRS causes Raman shift of the pump signal to amplify the information signal, resulting in amplified signals that are efficiently coupled out of the relatively small core diametered optical fiber with another single-mode optical fiber taper portion.

Abstract: An apparatus and method are provided to homogenize the intensity profile of the beam emitted by an excimer laser. The excimer laser beam is collected by a closely packed ultraviolet-grade optical fiber bundle array having its individual fibers intermingled in a random or preconceived format to result in an intermixing of the light from the individual fiber cores to produce a uniform intensity profile. The output ends of the fibers are gathered or fused, and optionally tapered. before being cleaved to provide an output face that is custom shaped for a desired illumination pattern. The flexible nature of the fiber bundle allows for remote materials processing applications.

Abstract: By incorporating a phase-conjugating process (Stimulated Brillouin Scatteg) with a master oscillator power amplifier laser cavity, a new phase conjugate resonator (PCR) is obtained. The PCR utilizes flashlamp-pumped dye lasers and a resonator cavity that is formed by a 100% mirror on one end and a Stimulated Brillouin Scattering (SBS) cell on the other end. The SBS cell functions as one of the mirrors of the resonator and causes the entire system to operate as a phase conjugate resonator. The result is vastly improved (an order of magnitude) beam qualities over conventional resonators for large lamp systems.