In situ measurement of gas composition changes in radio frequency plasmas using a quartz sensor

Suzuki, Atsushi; Nonaka, Hidehiko
September 2009
Review of Scientific Instruments;Sep2009, Vol. 80 Issue 9, p095109
Academic Journal
A simple method using a quartz sensor (Q-sensor) was developed to observe gas composition changes in radio frequency (rf) plasmas. The output depends on the gases’ absolute pressure, molecular weight, and viscosity. The pressure-normalized quartz sensor output depends only on the molecular weight and viscosity of the gas. Consequently, gas composition changes can be detected in the plasmas if a sensor can be used in the plasmas. Influences imparted by the plasmas on the sensor, such as those by reactive particles (e.g., radicals and ions), excited species, electrons, temperature, and electric potentials during measurements were investigated to test the applicability of this quartz sensor measurement to plasma. The Q-sensor measurement results for rf plasmas with argon, hydrogen, and their mixtures are reproducible, demonstrating that the Q-sensor measurement is applicable for plasmas. In this work, pressure- and temperature-normalized Q-sensor output (NQO) were used to obtain the gas composition information of plasma. Temperature-normalization of the Q-sensor output enabled quartz sensor measurements near plasma electrodes, where the quartz sensor temperature increases. The changes in NQO agreed with results obtained by gas analysis using a quadrupole mass spectrometer. Results confirmed that the change in NQO is mainly attributable to changes in the densities and kinds of gas molecules in the plasma gas phase, not by other extrinsic influences of plasma. For argon, hydrogen, and argon-hydrogen plasmas, these changes correspond to reduction in nitrogen, production of carbon monoxide, and dissociation of hydrogen molecules, respectively. These changes in NQO qualitatively and somewhat quantitatively agreed with results obtained using gas analysis, indicting that the measurement has a potential application to obtain the gas composition in plasmas without disturbing industrial plasma processes.


Related Articles

  • Laboratory cool. Beazant, Gareth // Professional Engineering;4/12/2006, Vol. 19 Issue 7, p48 

    The article introduces the iCap 6000 series, latest emission spectrometer used to measure the metallic concentration of elements, made by Thermo Electron Corp. in Great Britain. It is designed to occupy less laboratory space, while injection molding is utilized to reduce its price per part. The...

  • Self-integrating inductive loop for measuring high frequency pulses. Rojas-Moreno, Mónica V.; Robles, Guillermo; Martínez-Tarifa, Juan M.; Sanz-Feito, Javier // Review of Scientific Instruments;Aug2011, Vol. 82 Issue 8, p085102 

    High frequency pulses can be measured by means of inductive sensors. The main advantage of these sensors consists of non-contact measurements that isolate and protect measuring equipment. The objective of this paper is to present the implementation of an inductive sensor for measuring rapidly...

  • ENERGY HARVESTING PERPETUALLY POWERS WIRELESS SENSORS. Ostaffe, Harry // Wireless Design & Development;Jul/Aug2011, Vol. 19 Issue 4, p10 

    The article focuses on the use of micro-power energy harvesting to provide power to sensors autonomously without primary batteries or wires. It says that electrical energy is produced from waste energy from ambient sources in the harvesting process. It mentions several energy-harvesting...

  • Bolometric technique for high-resolution broadband microwave spectroscopy of ultra-low-loss samples. Turner, P.J.; Broun, D.M.; Kamal, Saeid; Hayden, M.E.; Bobowski, J.S.; Harris, R.; Morgan, D.C.; Preston, J.S.; Bonn, D.A.; Hardy, W.N. // Review of Scientific Instruments;Jan2004, Vol. 75 Issue 1, p124 

    A novel low-temperature bolometric method has been devised and implemented for high-precision measurements of the microwave surface resistance of small single-crystal platelet samples having very low absorption, as a continuous function of frequency. The key to the success of this nonresonant...

  • Inverted time-of-flight spectrometer for mass-to-charge analysis of plasma. Gushenets, V. I.; Burachevsky, Yu. A.; Vizir, A. V.; Oks, E. M.; Savkin, K. P.; Tynkov, A. V.; Yushkov, G. Yu. // Review of Scientific Instruments;2014, Vol. 85 Issue 2, p1 

    The paper describes the principle of operation, design special features, and parameters of an inverted time-of-flight spectrometer. The spectrometer is designed in such way that its deflecting plates, drift tube, and primary measuring system are at high potential with respect to the ground...

  • For Just Pennies, Boost Current From Negative Linear Regulator. Olson, Chad L. // Electronic Design;11/25/2002, Vol. 50 Issue 25, p71 

    Focuses on the role of a pass transistor and associated resistors in increasing load in a negative linear regulator. Connection of SET terminal to the ground keys; Reduction of power dissipation; Prevention of oscillation.

  • Current-sensing scheme improves PFC on/off sequences. Travis, Bill // EDN Europe;Jul2002, Vol. 47 Issue 7, p47 

    Focuses on the improvement of power factor correction on and off sequences in current-sensing scheme. Benefits of semiconductors; Phases of the boost structure; Modification of current-sensing resistor placement.

  • Switching regulator forms constant-current source. Strozecki, Stefan // EDN;5/30/2002, Vol. 47 Issue 12, p92 

    Discusses the problem on using a linear regulator in high current source because of the high power dissipation in the series resistor. Importance of good common-mode rejection and a wide common-mode voltage range; Dependence of the required gain on the output current needed; Overall gain of the...

  • Data acquisition unit measures current.  // Electronics Weekly;1/28/2004, Issue 2131, p36 

    MultiLog is a general purpose, four channel data acquisition module for laboratory or field measurement applications manufactured by Nicon. The module comes with a choice of ten programmable voltage ranges and true differential or unipolar inputs. Onboard shunt resistors extends its capabilities...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics