Chamber pressure

About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.

Flow ripple reduction of an axial piston pump by a combination of cross-angle and pressure relief grooves: Analysis and optimization

Abstract: This paper investigates the potential of flow ripple reduction of an axial piston pump by a combination of cross-angle and pressure relief grooves. A dynamic model is developed to analyze the pumping dynamics of the pump and validated by experimental results. The effects of cross-angle on the flow ripples in the outlet and inlet ports, and the piston chamber pressure are investigated. The effects of pressure relief grooves on the optimal solutions obtained by a multi-objective optimization method are identified. A sensitivity analysis is performed to investigate the sensitivity of cross-angle to different working conditions. The results reveal that the flow ripples from the optimal solutions are smaller using the cross-angle and pressure relief grooves than those using the cross-angle and ordinary precompression and decompression angles and the cross-angle can be smaller. In addition, when the optimal design is used, the outlet flow ripples sensitivity can be reduced significantly.

Ionized physical vapor deposition apparatus using helical self-resonant coil

Abstract: Provided is an ionized physical vapor deposition (IPVD) apparatus having a helical self-resonant coil. The IPVD apparatus comprises a process chamber having a substrate holder that supports a substrate to be processed, a deposition material source that supplies a material to be deposited on the substrate into the process chamber, facing the substrate holder, a gas injection unit to inject a process gas into the process chamber, a bias power source that applies a bias potential to the substrate holder, a helical self-resonant coil that produces plasma for ionization of the deposition material in the process chamber, one end of the helical self-resonant coil being grounded and the other end being electrically open, and an RF generator to supply an RF power to the helical self-resonant coil. The use of a helical self-resonant coil enables the IPVD apparatus to ignite and operate at very low chamber pressure such as approximately 0.1 mtorr, and to produce high density plasma with high efficiency compared to a conventional IPVD apparatus. Accordingly, a high efficiency of ionization of deposition material is achieved.

Effects of High-Pressure Buffer Gases on Emission from Laser-Induced Plasmas

Abstract: A laser-induced plasma is used for atomization, ionization, and excitation of elements in solid samples. The analytes are placed in a variable-pressure chamber in which the surrounding gas can be modified to obtain optimum emission characteristics for a particular sample. A time-resolved system is described which can produce qualitative and semi-quantitative spectroscopic information using a single laser plasma. The effects of the plasma position relative to the sample, the chamber pressure, and the characteristics of the surrounding gases are studied. When helium was employed as the buffer gas, maximum emission intensity for the aluminum ionic transition at 281.6 nm was observed. The spectra obtained show that it is possible to obtain qualitative spectroscopic information with the formation of single plasmas by the use of time resolution. It is also demonstrated that sample excitation can be achieved directly by the plasma and indirectly by energy transfer from gases in the chamber. This method allows the use of small sample quantities with little sample preparation and is especially advantageous for solid samples which are not easily dissolved.

Investigation of etching and deposition processes of Cl2/O2/Ar inductively coupled plasmas on silicon by means of plasma?surface simulations and experiments

Abstract: In this paper, a simulation method is described to predict the etching behaviour of Cl2/O2/Ar inductively coupled plasmas on a Si substrate, as used in shallow trench isolation for the production of electronic devices. The hybrid plasma equipment model (HPEM) developed by Kushner et al is applied to calculate the plasma characteristics in the reactor chamber and two additional Monte Carlo simulations are performed to predict the fluxes, angles and energy of the plasma species bombarding the Si substrate, as well as the resulting surface processes such as etching and deposition. The simulations are performed for a wide variety of operating conditions such as gas composition, chamber pressure, power deposition and substrate bias. It is predicted by the simulations that when the fraction of oxygen in the gas mixture is too high, the oxidation of the Si substrate is superior to the etching of Si by chlorine species, resulting in an etch rate close to zero as is also observed in the experiments.

Brake control method having booster runout and pedal force estimation

Abstract: An electrically augmented brake control method in which vacuum booster run-out and pedal force are accurately predicted as a function of master cylinder pressure and engine vacuum, thereby eliminating the expense of dedicated sensors for measuring the same. A mathematical model of the vacuum booster is used to estimate the apply chamber pressure and the operator brake pedal force, based on measured values of engine vacuum (or manifold absolute pressure) and master cylinder pressure. The point of vacuum booster runout can be detected as the point at which the estimated apply chamber pressure reaches atmospheric pressure. In a preferred embodiment, a force-balance approach is used to carry out the estimation in an accurate but simple manner that is especially amenable to real-time control in an automotive on-board micro-controller.