Abstract: Methods and arrangements are disclosed herein for optically storing data from a serial optical bit stream. As each bit of the optical stream is received it is applied to an optical storage medium e.g., lithium niobate, along with a reference beam. The angle of the reference beam is changed in synchronism with the received optical bits to create identifiable interference patterns for each bit.

Abstract: Methods and arrangements are disclosed herein for optically storing data from a serial optical bit stream. As each bit of the optical stream is received it is applied to an optical storage medium e.g., lithium niobate, along with a reference beam. The angle of the reference beam is changed in synchronism with the received optical bits to create identifiable interference patterns for each bit.

Abstract: Disclosed are silica structure crack detection methods and apparatuses particularly useful in sol-gel fabrication processes. A wave signature of a crack in the silica structure is sensed to indicate that cracking has occurred. Sensing may be by active or passive techniques and may include contact and non-contact methods of monitoring. Further disclosed is a silica structure fabrication process development method wherein cracks are monitored by sensing a wave signature of a crack to isolate a process step or steps in which cracking has occurred. Process parameters are then adjusted in the isolated step to diminish or eliminate cracking.

Abstract: A crack detection method and system capable of detecting cracks on a scale of about 5 &mgr;m or greater, useful for detecting cracks in sol-gel tubes. An electromagnetic radiation signal is transmitted from a sensor to a body in which cracking may occur. The signal is reflected back to and received by the sensor. An output voltage from the sensor is measured which is proportional to a signal characteristic change between the transmitted and received signals. Signal characteristics such as frequency, phase, and amplitude may be monitored. The signal characteristic change may result from one or more mechanisms selected from the group consisting of microscopic motion of the body, media transition and fluid movement.

Abstract: Disclosed are silica structure crack detection methods and apparatuses particularly useful in sol-gel fabrication processes. A wave signature of a crack in the silica structure is sensed to indicate that cracking has occurred. Sensing may be by active or passive techniques and may include contact and non-contact methods of monitoring.

Abstract: A crack detection method capable of detecting cracks on a scale of about 5 &mgr;m or greater, useful for detecting cracks in sol-gel tubes. A signal is transmitted from a source to a body in which cracking may occur. The signal is reflected back to a sensor. An output voltage from the sensor is measured which is proportional to a signal characteristic change between the transmitted and received signals. Signal characteristics such as frequency, phase, and amplitude may be monitored. The signal characteristic change may result from one or more mechanisms selected from the group consisting of microscopic motion of the body, media transition and fluid movement.

Abstract: A method for determining the endpoint of a plasma etch process is disclosed. The endpoint of the plasma etch process is determined using an acoustic cell attached to an exhaust port on a reaction chamber of a plasma reactor. The gas from the reaction chamber flows into the acoustic cell during the plasma etch process. Acoustic signals are periodically transmitted through the gas flowing in the acoustic cell and a first velocity for the acoustic signals associated with etching a first material layer formed on a substrate is determined. Thereafter, the endpoint of the plasma etch step is determined when the first velocity changes to a second velocity associated with etching the first material layer through its thickness to its interface with an underlying material layer. The gas from the reaction chamber flows through a compressor prior to flowing into the acoustic cell to increase the gas pressure in the acoustic cell.

Abstract: An apparatus is provided comprising means for creating substantially the same or mirror image first and a second gas flow patterns near the surface of first and second transducers. The means include an inlet conduit, an inlet port, a main conduit device, and an output port. A device is also provided for causing the first transducer to send a signal to the second transducer and for measuring the time taken for the signal to travel from first transducer to the second transducer. The inlet port is coupled to the inlet conduit, preferably centrally, and the output port is coupled to the main conduit device. The inlet conduit is comprised of a first branch and a second branch. Both branches have first and second ends, the second end of the first branch being coupled to the main conduit device at a first location, and the second end of the second branch being coupled to the main conduit device at a second location.

Abstract: A method for determining the endpoint of a plasma etch process is disclosed. The endpoint of the plasma etch process is determined using an acoustic cell attached to an exhaust port on a reaction chamber of a plasma reactor. At least a portion of the gas from the reaction chamber flows into the acoustic cell during the plasma etch process. Acoustic signals are periodically transmitted through the gas flowing in the acoustic cell and a first velocity for the acoustic signals associated with etching a first material layer formed on a substrate is determined. Thereafter, the endpoint of the plasma etch step is determined when the first velocity changes to a second velocity associated with etching the first material layer through its thickness to its interface with an underlying material layer. The gas from the reaction chamber optionally flows through a compressor prior to flowing into the acoustic cell. The compressor increases the pressure of the gas that flows into the acoustic cell.

Abstract: The present invention provides an acoustic cell for determining the composition of gas mixtures. The acoustic gas composition analysis cell has transducers isolated from the cell body by a metal housing. A sound-absorbing sleeve around the body of the transducer increases the signal-to-noise ratio to at least 4:1. Additionally, the transducers employed in the acoustic cell operate in the kilohertz range, reducing attenuation in the gas mixture being analyzed. The cell body employs vacuum seals which permit the use of the cell in line with vacuum equipment.

Abstract: The present invention provides improved processes and apparatus for fabrication of articles having silicon-containing regions. The process comprises generating silane by electrochemical reaction with a silicon-containing precursor material. An electrochemical cell generates H.sup.+ species which react with silicon from the precursor material to form a silane. The silane is used to deposit a silicon-containing article region. An apparatus for fabricating an article having a silicon-containing region is also provided. The fabrication system includes a reaction chamber having a gas supply line communicating with a silane-generating electrochemical cell. The electrochemical cell includes a first electrode for generating a supply of H.sup.+ ions, a silicon-containing precursor material in communication with the first electrode, a second electrode, and a receptacle for retaining an electrolyte.

Abstract: The present invention provides an acoustic cell for determining the composition of gas mixtures. The acoustic gas composition analysis cell has transducers acoustically isolated from the cell body through the use of an acoustic isolation material positioned at least between the transducers and the transducer housings to produce a signal-to-noise ratio of at least 4 to 1. Additionally, the transducers employed in the acoustic cell operate in the kilohertz range, reducing attenuation in the gas mixture being analyzed. The cell body employs vacuum seals which permit the use of the cell in line with vacuum equipment.

Abstract: Many devices, such as those based on III-V semiconductor materials, are produced utilizing gases such as arsine that require careful handling of compressed gas cylinders. This care has engendered a search for alternate approaches. It has been found that the use of electrochemically generated gases such as arsine yields an efficient, pure source of such gases without necessitating the storage of large gas quantities. Thus, a device fabrication procedure including in situ electrochemical generation of gases such as arsine is particularly useful.

Abstract: Many devices, such as those based on III-V semiconductor materials, are produced utilizing gases such as arsine that require careful handling of compressed gas cylinders. This care has engendered a search for alternate approaches. It has been found that the use of electrochemically generated gases such as arsine yields an efficient, pure source of such gases without necessitating the storage of large gas quantifies. Thus, a device fabrication procedure including in situ electrochemical generation of gases such as arsine is particularly useful.

Abstract: The present invention provides an acoustic cell for determining the composition of gas mixtures. The acoustic gas composition analysis cell has transducers acoustically isolated from the cell body through the use of an acoustic isolation material positioned at least between the transducers and the transducer housings to produce a signal-to-noise ratio of at least 4 to 1. Additionally, the transducers employed in the acoustic cell operate in the kilohertz range, reducing attenuation in the gas mixture being analyzed. The cell body employs vacuum seals which permit the use of the cell in line with vacuum equipment.