Showing papers on "Chamber pressure published in 1996"

Formation tester with improved sample collection system

Abstract: This invention provides a formation evaluation tool for collecting a formation fluid in a chamber at a predetermined pressure and for maintaining the pressure of the collected fluid at a desired level during the retrieval of the chamber to the surface. The formation fluid is pumped into the chamber while a piston exposed to the hydrostatic pressure maintains the chamber pressure at the hydrostatic pressure. During retrieval of the chamber, the pressure in the chamber is maintained at a predetermined level by pumping wellbore fluid to the piston. A control unit at the surface is utilized for controlling the operation of the formation tool.

Etching of 6H‐SiC and 4H‐SiC using NF 3 in a Reactive Ion Etching System

Abstract: The use of pure NF 3 source gas in reactive ion etching of bulk and epitaxy Si-face, 6H-SiC, and 4H-SiC is reported. The effects of RF power and chamber pressure on etch rate and surface morphology are discussed. A process developed for a smooth, residue-free etch, with a relatively high etch rate of ∼1500 A/min is examined using scanning electron microscopy and Auger electron spectroscopy surface analysis. The process developed had a self-induced dc bias ranging from 25 to 50 V, a forward RF power of 275 W (1.7 W/cm 2 ), chamber pressure of 225 mT, and a NF 3 flow rate between 95 and 110 sccm. No chemical residue or aluminum micromasking was observed on any of the samples etched with the above process.

Analysis of Current Spray Penetration Models and Proposal of a Phenomenological Cone Penetration Model

Abstract: A phenomenological zero-dimensional spray penetration model was developed for diesel-type conditions for a constant volume chamber. The spray was modeled as a protruding cone which is well-mixed at its tip after passing through initial primary and secondary breakup zones. The resulting cone model is strictly dependent on injection parameters: density ratio, injection and chamber pressure, nozzle characteristics, and cone angle. The proposed model was compared with data from three different sources and performed well in most cases except for low density environments.

Combustor oscillation attenuation via the control of fuel-supply line dynamics

Abstract: Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value.

Advanced HfC-TaC Oxidation Resistant Composite Rocket Thruster

Abstract: Several compositions of HfC-TaC codeposited by chemical vapor deposition were evaluated for oxidation protection of graphite substrates. Oxyacetylene torch ablation tests with an O2, C2, H2, ratio of 4:1 were used to test the adherence and composition of the coating and resulting oxides, which were subsequently characterized by x-ray diffraction and scanning electron microscopy. The preferred HfC-TaC composition of 70:30 was used to fabricate a 25 lbf graphite fiber reinforced rocket thruster with a unique structural design. Thruster testing at NASA Lewis was performed at 0.520 MPa chamber pressure and 1650°C (3000°F) using a 6 to 7:1,02,:H2 fuel mixture; a uniform, adherent oxide layer was observed on the internal surface of the combustion chamber following the test.

Plasma purge method for plasma process particle control

Abstract: A method for limiting contaminant particle deposition upon integrated circuit layers within plasma assisted process reactor chambers. First, there is undertaken a plasma assisted process upon an integrated circuit layer within a plasma assisted process reactor chamber. The plasma assisted process employs a reactant gas composition, a first radio frequency power and a first reactor chamber pressure appropriate to the plasma assisted process and the integrated circuit layer. There is then undertaken a first plasma purge step for a first purge time immediately following the plasma assisted process. The first plasma purge step employs a first purge gas composition, a second radio frequency power and a second reactor chamber pressure. The second radio frequency power is lower than the first radio frequency power and the second reactor chamber pressure is higher than the first reactor chamber pressure. Optionally, there may also be undertaken a second plasma purge step for a second purge time immediately following the first plasma purge step. The second plasma purge step employs a second purge gas composition, a third radio frequency power and a third reactor chamber pressure. The third radio frequency power is no greater than the second radio frequency power and the third reactor chamber pressure is lower than the second reactor chamber pressure.

Minimized response time of optical emission and mass spectrometric signals for optimized endpoint detection

Abstract: The response times of optical emission spectroscopy (OES) and mass spectrometry (MS) have been measured for plasma etching of III–V heterostructures. For the Ga optical emission signal at 417.2 nm, a response time as fast as 0.2 s was obtained. The minimum response time of the 145AsCl+2 partial pressure, measured by MS, was found to be 0.9 s. The saturation times of the optical emission signal and the partial pressure signal have been shown to be related to the residence time of etch gases by varying the total gas flow rate and the chamber pressure. Decreasing residence time by reducing the pressure from 6 to 2 mTorr and maintaining a constant flow rate caused the saturation time of the Ga emission signal at 417.2 nm to decrease from 7 to 3 min. The 145AsCl+2 partial pressure signal saturated before the Ga emission signal. Endpoint detection for etching an AlInAs emitter and stopping on a GaInAs base of a heterojunction bipolar transistor was studied. Algorithms which monitor the change in Ga emission int...

Semiconductor wafer manufacturing process with high-flow-rate low-pressure purge cycles

Abstract: A purge process for an LPCVD TEOS silicon dioxide deposition method uses a series of five purge cycles to allow low-defect wafer processing with less frequent chamber removal and cleaning. The purge process begins by loading dummy wafers into the chamber. Chamber pressure is reduced to below 20 mTorr. A maximal nonreactant gas flow for two minutes is used to dislodge and carry away contaminants such as flakes from silicon dioxide previously deposited on the chamber wall. After the first four of five purge cycles, the method returns to the reduction of chamber pressure, e.g., by maintaining the vacuum on while the gas sources are turned off. After the fifth cycle, the chamber is slowly filled with nitrogen until ambient pressure is reached. Then the dummy wafers are removed. The system is then ready for processing product wafers with reduced particle counts. The purge process is benign in that it only uses equipment and procedures of the type used during product wafer processing. Maintenance involving chamber removal and cleaning is required much less often so that manufacturing throughput is enhanced.

Enhanced adsorbent and room temperature catalyst particle and method of making therefor

Abstract: A method for producing an enhanced adsorbent and/or enhanced catalytic particle and/or for producing a catalytic particle, comprising the steps of: (a) removing an effective amount of air from a closed chamber containing an adsorbent and/or catalytic particle, wherein the resultant chamber pressure is less than one atmosphere; (b) raising the chamber pressure with an inert gas to at least one atmosphere; (c) contacting the particle with an energy beam of sufficient energy for a sufficient time to thereby enhance the adsorbent and/or catalytic properties of the particle and/or produce catalytic properties in the particle. A continuous process directed to step (c) alone is also provided. Also disclosed are adsorbent and/or catalytic particles, methods of contaminant reduction or elimination, including room temperature catalysis, particle binders, apparatuses of the present invention, and methods of increasing the surface area of adsorbent and/or catalytic particles.

Apparatus for sidewall profile control during an etch process

Abstract: A process is provided for controlling the slope of the sidewalls of an opening produced in a semiconductor wafer during an etch process Microwave or radio frequency energy is remotely applied to pre-excite a process gas Radio frequency energy is also supplied to the process gas within the process chamber The sidewall slope is varied by varying the ratio of the amount of remote microwave or radio frequency energy supplied and that of the radio frequency energy supplied within the process chamber The sidewall slope is also shaped by controlling the process gas flow rate and composition, and the pressure within the process chamber A more vertical, anisotropic etch profile is obtained with increased radio frequency energy and lower process chamber pressure A more horizontal, isotropic profile is obtained with decreased radio frequency energy and higher process chamber pressure A narrower etched feature having smaller interlayer and active element contact regions than the corresponding feature size on the overlying photoresist layer may thereby be provided

Dry etching of horizontal distributed Bragg reflector mirrors for waveguide lasers

Abstract: Distributed Bragg reflector mirrors were etched in InP and GaAs. The mirrors were patterned using electron‐beam lithography and etched with an electron cyclotron resonance source. This fabrication technique has the advantage that no regrowth step is required and the length of the passive mirror region is confined to a few micrometers. The structure requires etching vertical profiles with smooth surface morphology and high selectivity to the masking material. The effects of rf power, Cl2 percentage in Ar, chamber pressure, and stage temperature were studied. Increasing the rf power from 100 to 250 W caused the InP selectivity to Ni to decrease from 147 to 55. A similar effect was observed for etching GaAs. For both InP and GaAs, a vertical profile can be obtained by reducing the Cl2 percentage in Ar and by using low chamber pressure of 1 mTorr. Increasing the Cl2 percentage, however, improves selectivity to the Ni mask. With 20% Cl2 in Ar, vertical profiles and high selectivities are obtained for both InP ...

Spraycast method and article

Abstract: Spraycasting method involves directing an atomized metal or alloy spray at a collector disposed in a spray chamber and controlling temperature of the spray in flight in the spray chamber and of the atomized metal or alloy as it is deposited on the collector by a spray chamber pressure control technique that involves in-situ evacuation of the spray chamber during spray deposition to a maintain spray chamber gas partial pressure less than about 400 torr. Such low spray chamber gas partial pressure provides a higher temperature of the atomized spray in flight in the spray chamber and of the sprayed material as it is deposited on a collector in the spray chamber effective to reduce deposit porosity, reduce grain layering or banding, and provide a uniform grain through the thickness of the deposit.

Seal arrangement for engine-driven supercharger

Abstract: A seal arrangement for an engine-driven supercharger to prevent burning and abnormal wear of an rubber-made oil seal fitted on a shaft of a rotor of the supercharger. The supercharger includes a housing, a rotor chamber is formed in the housing and the rotor is rotatably placed in the rotor chamber. A shaft chamber is formed next to the rotor chamber. The rotor shaft projects from the rotor chamber into the shaft chamber in a longitudinal direction of the rotor. A bearing is provided inside the shaft chamber for supporting the rotor shaft at a free end of the rotor shaft. A lubrication oil is fed to the bearing. The supercharger sucks external air into the rotor chamber by making the rotor chamber pressure negative and rotates the rotor for compressing the air in the rotor chamber. The oil seal is fitted on the rotor shaft between the bearing and the rotor chamber for defining an oil chamber in the shaft chamber between the oil seal and the bearing. An air chamber is defined in the shaft chamber between the oil seal and the rotor chamber. An air passage extends from the air chamber to the outside so that positive or negative pressure of the air leaking to the air chamber from the rotor chamber is lowered or raised when the air enters the air chamber which communicates with the outside via the first air passage.

Apparatus for and method of ion detection using electron multiplier over a range of high pressures

Abstract: Ions in a chamber or space are detected using an electron multiplier operating at relatively low gain. The electron multiplier is placed in communication with the chamber, such as a chamber of a mass spectrometer, such that ions from the chamber enter the electron multiplier. A bias voltage applied to the multiplier sets the gain of the multiplier. By setting the gain at a relatively low value, the gain of the multiplier remains independent of chamber pressure, such that an accurate pressure measurement is obtained without calibration at a particular pressure or as a function of pressure.

Electrode plate and manufacture thereof

Abstract: PROBLEM TO BE SOLVED: To provide an electrode plate having a large surface area and high reliability, in which peeling is not generated with temperature change, by forming a carbon thin film in a surface of a substrate, which is formed with projecting parts and recessed parts at a specified depth, by a chemical vapor deposition method. SOLUTION: A surface of an electrode plate, which is formed of a copper foil 10 at about 20μm of thickness, is formed with recessed parts and projecting parts at 1-100nm of depth by using a roller (b), and thereafter, in the condition at about 700 deg.C of substrate temperature and at about 0.1Torr of chamber pressure, a predetermined quantity of methane, argon and hydrogen are made to flow into a chamber, and a carbon thin film 11 at about 100μm of thickness is formed by using CVD method (c). With this structure, a film adhesive property is remarkably improved. The adhesive property is more improved by interposing a single layer or multi-layer structural film of the alloy of Fe, Co. Ni or carbide thereof as an intermediate layer between the substrate and the carbon thin film. At the time of vapor phase epitaxy, in the case where gas is used for plasma jetting method, a film having multiple standing pieces can be obtained, and a film having a remarkably large surface are can be obtained.

Enhanced adsorbent and room temperature catalyst particle and method of making and using therefor

Abstract: A method for producing an enhanced adsorbent and/or enhanced catalytic particle and/or for producing a catalytic particle, comprising the steps of: (a) removing an effective amount of air from a closed chamber containing an adsorbent and/or catalytic particle, wherein the resultant chamber pressure is less than one atmosphere; (b) raising the chamber pressure with an inert gas to at least one atmosphere; (c) contacting the particle with an energy beam of sufficient energy for a sufficient time to thereby enhance the adsorbent and/or catalytic properties of the particle and/or produce catalytic properties in the particle. A continuous process directed to step (c) alone is also provided. Also disclosed are adsorbent and/or catalytic particles, methods of contaminant reduction or elimination, including room temperature catalysis, particle binders, apparatuses of the present invention, and methods of increasing the surface area of adsorbent and/or catalytic particles.

In situ fiber optic thermometry of wafer surface etched with an electron cyclotron resonance source

Abstract: The effect of plasma heating on wafer temperature during etching has been studied. Si and InP were etched using a high ion density discharge generated by an electron cyclotron resonance source. The wafer temperature was measured using fiber optic thermometry as microwave power, rf power, chamber pressure, and gas flow were varied. Wafer temperatures increased with both rf and microwave power, and decreased with chamber pressure. For a rf power of 50 W, chamber pressure of 1 mTorr, a source distance of 13 cm, and a 10 sccm Ar flow, an increase in microwave power from 50 to 500 W caused the temperature to increase from 62 to 186 °C. An increase in the rf power from 50 to 300 W increased the wafer temperature to 145 °C. Additionally, the effectiveness of using He flowing at the backside of the wafer for temperature control was analyzed. By setting the backside He pressure at 3 Torr, the temperature increased to only 29 °C. Time dependent etch characteristics of InP were studied and related to the in situ temperature measurements. At 100 W of microwave power, the InP etch rate increased from 100 to 400 nm/min as the wafer temperature rose from 20 to 150 °C. As the temperature increased above 150 °C, the profile became more undercut and the surface morphology improved. By setting the stage temperature to −100 °C and using 3 Torr of He pressure at the backside of the wafer, the InP etch rate remained constant during etching and undercutting was suppressed. For 500 W of microwave power, a fast InP etch rate of 2 μm/min was obtained when the wafer temperature was <110 °C, and it increased to over 4 μm/min when the temperature was ≳150 °C.

Correlation of slag expulsion with ballistic anomalies in Shuttle solid rocket motors

Abstract: During the Shuttle launches, the solid rocket motors (SRM) occasionally experience pressure perturbations (8-13 psi) between 65-75 s into the motor burn time. The magnitudes of these perturbations are very small in comparison with the operating motor chamber pressure, which is over 600 psi during this time frame. These SRM pressure perturbations are believed to he caused primarily by the expulsion of slag (aluminum oxide). Two SRM static tests, TEM-11 and FSM-4, were instrumented extensively for the study of the phenomena associated with pressure perturbations. The test instrumentation used included nonintrusive optical and infrared diagnostics of the plume, such as high-speed photography, radiometers, and thermal image cameras. Results from all of these nonintrusive observations provide substantial circumstantial evidence to support the scenario that the pressure perturbation event in the Shuttle SRM is caused primarily by the expulsion of molten slag. In the static motor tests, the slag was also expelled preferentially near the bottom of the nozzle because of slag accumulation at the bottom of the aft end of the horizontally oriented motor.

Vehicle air conditioning apparatus

Abstract: Carbon dioxide in a closed circuit (2) is circulated by a compressor (1) and via two or more heat-exchangers (3,5) in-series. On one side of the circuit the compressor is situated between the exchangers, while on the other there is an expansion valve (4) between them. The compressor is regulated by the pressure in its driving chamber (18). A tapping (22) leads from the circuit to the chamber and from there back to it at the compressor suction side, and contains flow-limiting (21) and regulating valves (23) for the chamber pressure. Seen in the flow direction in the circuit (2), the tapping is situated between the first exchanger (5) and the expansion valve (4), so that it cools the compressor.

Reactive ion etching of gallium nitride films

Abstract: Reactive ion etching (RIE) was performed on gallium nitride (GaN) films grown by electron cyclotron resonance (ECR) plasma assisted molecular beam epitaxy (MBE). Etching was carried out using trifluoromethane (CHF3) and chloropentafluoroethane (C2ClF5) plasmas with Ar gas. A conventional rf plasma discharge RIE system without ECR or Ar ion gun was used. The effects of chamber pressure, plasma power, and gas flow rate on the etch rates were investigated. The etch rate increased linearly with the ratio of plasma power to chamber pressure. The etching rate varied between 60 and 500A/min, with plasma power of 100 to 500W, chamber pressure of 60 to 300 mTorr, and gas flow rate of 20 to 50 seem. Single crystalline GaN films on sapphire showed a slightly lower etch rate than domain-structured GaN films on GaAs. The surface morphology quality after etching was examined by atomic force microscopy and scanning electron microscopy.

Method and apparatus for testing the brake system of a vehicle

Abstract: For the detection of undissolved gas in the brake system; hydraulic pressure is built up and at least one characteristic value for the pressure buildup such as the master cylinder pressure, the brake pedal distance, the drop in storage chamber pressure, etc., is checked to see if it exceeds a predetermined limit value. If this limit value is exceeded, it is assumed that there is an unacceptable amount of undissolved gas in the hydraulic component of the brake system.

Valved suction mechanism for refrigerant compressor

Abstract: A refrigerant compressor includes a compressor housing divided by a valve plate into a first chamber and a second chamber. The valve plate includes suction conduits linking the first chamber with the suction chamber and discharge conduits linking the first chamber with the discharge chamber. A suction valve member bends to open and close the suction conduits in response to changes in discharge chamber pressure and the resulting pressure difference between the first chamber and the suction chamber. A suction valve control mechanism includes a regulator for regulating the opening and closing of the suction conduit between a maximum opening position and a minimum opening position in response to changes in discharge chamber pressure. Consquently, a starting torque shock to the compressor is reduced while maintaining high volumetric efficiency of the compressor.

Characterization of fuel regression in a radial flow hybrid rocket

Abstract: Reliable ignition and stable combustion have been achieved in a lab-scale radial-e ow hybrid rocket engine. The device utilizes 85% hydrogen peroxide and polyethylene and was tested at chamber pressures ranging from 118 to 238 psia. Fuel regression behavior was characterized with respect to initial geometry and mass e ux. The measured regression rates are greater than observed in axial port designs at the same e ux and chamber pressure levels. Although the regression behavior is effected locally by the three-dimensional e ow structure, the results were more uniform than predicted by lumped parameter ballistics approximations. For this reason, radial-e ow designs with acceptable fuel utilization appear to be feasible.

Deflection controllable roller for use in calender

Abstract: A deflection controllable roller has as an on-off valve disposed in each of a plurality of discharge lines. The on-off valve opens only toward the discharge side. The discharge side of the on-off valve is alternately pressurized with an opening pressure that is less than an internal chamber pressure or with a cut-off pressure that is greater than the internal chamber pressure. The on-off valves are located directly in the bearing device and are, therefore, relatively easily controlled.

The Effect of Pressure on Power Transfer in Electron Beam Remelting of Cylinders

Abstract: Measurements have been made in a laboratory scale furnace to examine the effect of chamber pressure on power deposition in electron beam remelting. Both commercial purity titanium and tantalum cylinders instrumented with embedded thermocouples have been used as targets in the study. Owing to the fact that a direct measurement of the power distribution was not possible, a finite element based transient heat conduction model has been employed to analyze the measurements. The results of the analysis indicate that the distribution of power density can be adequately described as a normal Gaussian and that the beam is focused as the pressure is increased from low to moderate pressures (0.004 to 0.15Pa) then gradually defocused as the pressure continues to increase (0.15 to 0.8Pa). A detailed examination of the data with the model indicates that the predominant effect of pressure is to alter the beam focus and not the amount of power deposited. A comparison of the results obtained from the tantalum target, where no liquid metal was present, and the titanium target, where liquid metal was present, indicates that liquid metal vapor acts to defocus the beam. Finally, an examination of the effect of pressure on the behavior of the liquid pool indicates that the predominant effect of defocusing is to alter the pool depth.

Automated becker hammer drill bounce chamber energy monitor

Abstract: A system and method for providing analysis and evaluation of penetration test data for modifying Becker Hammer drill programs while in progress by measuring the bounce chamber pressure of a diesel hammer. The system comprises a pressure transducer connected to the bounce chamber for sensing the bounce chamber pressure, a data logger for monitoring the pressure transducer, storage means, a control module and a keyboard having a display screen to enable user control of the data logger, a telephone modem, and a series of instructions for controlling the schedule, pressure transducer measurement, control module signal monitoring, computation of data, and data storage operations of the data logger.