1277 results about "Gas composition" patented technology

We have discovered that adding H₂ to a precursor gas composition including SiH₄, NH₃, and N₂ is effective at improving the wet etch rate and the wet etch rate uniformity across the substrate surface of a-SiN_x:H films which are deposited on a substrate by PECVD. Wet etch rate is an indication of film density. Typically, the lower the wet etch rate, the denser the film. The addition of H₂ to the SiH₄/NH₃/N₂ precursor gas composition did not significantly increase the variation in deposited film thickness across the surface of the substrate. The a-SiN_x:H films described herein are particularly useful as TFT gate dielectrics in the production of flat panel displays. The uniformity of the film across the substrate enables the production of flat panel displays having surface areas of 25,000 cm² and larger.

The present invention provides straight forward methods for plasma etching a trench having rounded top corners, or rounded bottom corners, or both in a silicon substrate. A first method for creating a rounded top corner on the etched silicon trench comprises etching both an overlying silicon oxide layer and an upper portion of the silicon substrate during a "break-through" step which immediately precedes the step in which the silicon trench is etched. The plasma feed gas for the break-through step comprises carbon and fluorine. In this method, the photoresist layer used to pattern the etch stack is preferably not removed prior to the break-through etching step. Subsequent to the break-through step, a trench is etched to a desired depth in the silicon substrate using a different plasma feed gas composition. A second method for creating a rounded top corner on the etched silicon trench comprises formation of a built-up extension on the sidewall of an overlying patterned silicon nitride hard mask during etch (break-through) of a silicon oxide adhesion layer which lies between the hard mask and a silicone substrate. The built-up extension upon the silicon nitride sidewall acts as a sacrificial masking material during etch of the silicon trench, delaying etching of the silicon at the outer edges of the top of the trench. This permits completion of trench etching with delayed etching of the top corner of the trench and provides a more gentle rounding (increased radius) at the top corners of the trench. During the etching of the silicon trench to its final dimensions, it is desirable to round the bottom corners of the finished silicon trench. We have discovered that a more rounded bottom trench corner is obtained using a two-step silicon etch process where the second step of the process is carried out at a higher process chamber pressure than the first step.

A plasma reactor for processing a workpiece such as a semiconductor wafer has a housing defining a process chamber, a workpiece support configured to support a workpiece within the chamber during processing and comprising a plasma bias power electrode. The reactor further includes plural gas sources containing different gas species, plural process gas inlets and an array of valves capable of coupling any of said plural gas sources to any of said plural process gas inlets. The reactor also includes a controller governing said array of valves and is programmed to change the flow rates of gases through said inlets over time. A ceiling plasma source power electrode of the reactor has plural gas injection zones coupled to the respective process gas inlets. In a preferred embodiment, the plural gas sources comprise supplies containing, respectively, fluorocarbon or fluorohydrocarbon species with respectively different ratios of carbon and fluorine chemistries. They further include an oxygen or nitrogen supply and a diluent gas supply. The controller is programmed to produce flow of different process gas species or mixtures thereof through different ones of said plural gas injection zones. The controller is further programmed to change over time the species content of the gases flowing through different ones of said plural gas injection zones.

In a procedure to recognize the gas composition of a gas mixture, which consists of at least two gases of preferably different diffusion properties, delivered to a wideband lambda sensor, especially a gas mixture of an exhaust gas of an internal combustion engine of a motor vehicle, whereby the lambda sensor has a pumping cell with at least one gas measurement chamber, provision is made for the recognition of the gas composition of the gas mixture to result by means of modulation of the gas in the gas measurement chamber. Preferably the air number in the gas measurement chamber of the pumping cell is periodically altered, whereby the sensitivity of the lambda sensor to the gases, of which there are at least two, likewise periodically changes.

The present invention relates to a continuous gas phase process comprising polymerizing one or more hydrocarbon monomer(s) in a fluidized bed reactor in the presence of catalyst system or polymerization catalyst and a condensable fluid for a period of at least 12 hours where the bed temperature is less than the Critical Temperature and the dew point temperature of the gas composition in the reactor is within 25° C. of the bed temperature.

A system for determining gas compositions includes a probe, inserted into a source of gaseous material, the probe having a gas permeable sensor tip and being capable of sending and receiving light to and from the gaseous material, a sensor body, connected to the probe, situated outside of the source and a fiber bundle, connected to the sensor body and communicating light to and from the probe. The system also includes a laser source, connected to one portion of the fiber bundle and providing laser light to the fiber bundle and the probe a Raman spectrograph, connected to another portion of the fiber bundle, receiving light from the probe and filtering the received light into specific channels and a data processing unit, receiving and analyzing the received light in the specific channels and outputting concentration of specific gas species in the gaseous material based on the analyzed received light.

A bioreactor assembly of the present invention for holding a media and supporting growth of a plurality of plants. The assembly includes a light source and a container having a light transmissive wall structure and defining a reservoir. A major axis of the reservoir is substantially horizontal allowing the reservoir to be filled with media to a partial level and to define a relatively large surface area for support of the plants. The assembly may also include clamps to secure and seal separate wall structure portions of the container together, and end caps to the wall portions, to define an aseptic environment. As another option, the clamps may define openings therethrough that allow passage of various devices for measuring and controlling bioreactor function such as a gas supply nozzle, a gas exit nozzle, an air temperature probe, a pH probe, a sampling drain, a gas composition probe and a media temperature probe.

A gas chromatograph having the capability of performing a reliable measurement under a condition that the baseline of a detector output is stabilized, and a breath component analyzer using the same are provided. This gas chromatograph comprises a gas separation column accommodating a member for causing a flow delay depending on gas component; air pump for supplying an air as a carrier gas into the gas separation column; gas supply port formed in a gas flow channel extending between the air pump and the gas separation column, and adapted to supply a subject gas containing a target gas component to be detected into the carrier gas flowing in the gas flow channel; buffer tank provided upstream of the gas supply port; and a detector for detecting the gas component of the subject gas supplied into the gas separation column.

Disclosed is an MCFC power generation system and a method for operating the same enabling significant reduction of CO₂ emission or substantially zero CO₂ emission by minimizing the equipment added to a general power generation facility to a minimum, enabling both high power generation efficiency and high heat recovery efficiency, enabling adjustment of the voltage and output of the fuel cell in a certain range by adjusting the cathode gas composition, enabling great variation of the ratio between the heat and electricity, and thereby enabling variable thermoelectric operation. The MCFC generation system includes a cathode gas circulation system in which the cathode gas is circulated by a cathode gas recycle blower, and a closed loop is formed. Oxygen consumed by power generation is supplied from an oxygen supply plant, and CO₂ is supplied from recycled CO₂. Combustible components in anode exhaust are burned with oxygen, the resultant gas is cooled, and water is removed. The fuel gases in the anode exhaust is recycled.

The subject invention relates to a new alarm which is based on using a quarternary tunable Mid-IR laser to measure both particles and gas at the same time. The measurement is done within an area of which the gas of interest will absorb the Mid-IR radiation. By widely tuning the emission wavelength of the laser, several wavelengths can be measured in order to accurately find both gas composition and particle density with one laser based sensor. We tested a new device which use radiation between 2.27 μm and 2.316 μm. Methane gas reduces intensity of the radiation at certain wavelengths in this device, while particles/fog reduce intensity for all wavelengths. In this case, fog should not trigger an alarm, while methane leaks should. This can also be applied for CO and smoke in which one sensor will measure both parameters to sound an alarm instead of just one parameter.

The invention is a method and apparatus capable of detecting constituents of a gas at extremely low concentrations comprising providing a medium that is absorbent of at least a first particular gas under a first environmental condition and desorbent of the particular gas under a second environmental condition, exposing the medium to a sample gas for a first period of time under the first environmental condition, during a second period of time after the first period of time, exposing the medium to the second environmental condition to cause the medium to desorb gas into an optical cavity of a cavity ring down spectrometer and introducing electromagnetic radiation into the cavity, during a third period of time after the second period of time, ceasing introduction of the electromagnetic radiation into the cavity and detecting the decay of the electromagnetic radiation in the cavity, and analyzing the decay of the light in the cavity to obtain a spectral analysis of the sample gas.