skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Inverted-magnetron cold-cathode gauge in hybrid-discharge mode

Abstract

In high-vacuum measurement, cold-cathode ionization gauges have been widely used due to their unique advantages such as being simple and robust, low outgassing, x-ray effects, and so on. But during the measuring process, they show that a considerable pump effect, contamination buildup, and the heating and sputtering of the electrode surface from discharge can also become a serious problem at higher measured pressures. In such circumstances, pulsed operation is a good solution. However, the lowest measurable pressure of cold-cathode ionization gauges in pulsed operation is hard to extend, which limits its application. But if the measurable range of the cold-cathode gauge is divided into two regions, the low-pressure region where it is operated in dc discharge mode to ensure its lowest measurable pressure and the high-pressure region where it is operated in pulsed-discharge mode to reduce its above disadvantages at high pressures, the problem can be well solved. This article describes a pulsed high-voltage generating circuit controlled by a single-chip CPU to perform such a hybrid discharge in an inverted-magnetron gauge. With this circuit, the following problems of an inverted-magnetron gauge were investigated: the difference between pulsed-discharged mode and dc discharge mode, one method of extending the low measurable pressuremore » limit in pulsed-discharge mode, the volt-current characteristics at different pressures, and constant-current pulsed-discharge measurement at pressures above 2x10{sup -2} Pa.« less

Authors:
;  [1]
  1. School of Electrical Engineering, Beijing Jiaotong University, 100044 Beijing (China)
Publication Date:
OSTI Identifier:
20979386
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films; Journal Volume: 25; Journal Issue: 2; Other Information: DOI: 10.1116/1.2464122; (c) 2007 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CATHODES; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; HEATING; HYBRIDIZATION; IONIZATION; IONIZATION GAGES; MAGNETRONS; PRESSURE RANGE MEGA PA 10-100; SPUTTERING; SURFACES

Citation Formats

Mao Huiyong, and Wang Yi. Inverted-magnetron cold-cathode gauge in hybrid-discharge mode. United States: N. p., 2007. Web. doi:10.1116/1.2464122.
Mao Huiyong, & Wang Yi. Inverted-magnetron cold-cathode gauge in hybrid-discharge mode. United States. doi:10.1116/1.2464122.
Mao Huiyong, and Wang Yi. Thu . "Inverted-magnetron cold-cathode gauge in hybrid-discharge mode". United States. doi:10.1116/1.2464122.
@article{osti_20979386,
title = {Inverted-magnetron cold-cathode gauge in hybrid-discharge mode},
author = {Mao Huiyong and Wang Yi},
abstractNote = {In high-vacuum measurement, cold-cathode ionization gauges have been widely used due to their unique advantages such as being simple and robust, low outgassing, x-ray effects, and so on. But during the measuring process, they show that a considerable pump effect, contamination buildup, and the heating and sputtering of the electrode surface from discharge can also become a serious problem at higher measured pressures. In such circumstances, pulsed operation is a good solution. However, the lowest measurable pressure of cold-cathode ionization gauges in pulsed operation is hard to extend, which limits its application. But if the measurable range of the cold-cathode gauge is divided into two regions, the low-pressure region where it is operated in dc discharge mode to ensure its lowest measurable pressure and the high-pressure region where it is operated in pulsed-discharge mode to reduce its above disadvantages at high pressures, the problem can be well solved. This article describes a pulsed high-voltage generating circuit controlled by a single-chip CPU to perform such a hybrid discharge in an inverted-magnetron gauge. With this circuit, the following problems of an inverted-magnetron gauge were investigated: the difference between pulsed-discharged mode and dc discharge mode, one method of extending the low measurable pressure limit in pulsed-discharge mode, the volt-current characteristics at different pressures, and constant-current pulsed-discharge measurement at pressures above 2x10{sup -2} Pa.},
doi = {10.1116/1.2464122},
journal = {Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films},
number = 2,
volume = 25,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • A cold-cathode ionization gage with axial magnetic field is described which is capable of measuring pressure in the range 10/sup -3/ to 10/sup -12 mm Hg, and is primarily useful in the range above 5 x 10/sup -10/ mm Hg. The gage is operated with an anode voltage of 6 kilovolts and a magnetic field of 1000 gauss. The relationship between ion current and pressure is linear in the pressure rana 10/sup -4/ to 5 x 10/sup -10/ mm Hg; at lower pressures the relationship i/sub +/ = cP/sup 1.7/ holds. In the linear region the ion current per unitmore » pressure is given by i/sub +/ (amperes) = 9P (mm Hg) for nitrogen (i.e., a sensitivity abcut 45 times greater than obtainable with a thermionic triode gage). (auth)« less
  • In the high-pressure mode of a cold-cathode Penning discharge, an extensive study of the behavior of a rotationally symmetric wave, excited by a positive radial electron-temperature gradient, is made by utilizing a simple analog correlator. Several important experimental results, concerning the influence of the discharge parameters on the coherence and the frequency of the excited waves, are obtained and these are found to agree well with the theoretical predictions. The mechanism of the low-frequency waves in the high-pressure mode is also ascertained in this report.
  • The plasma parameters and reaction kinetics in an inverted cylindrical magnetron chamber have been studied with an energy resolved mass spectrometer during the sputtering of aluminum targets in an Ar/O{sub 2} discharge. Mixtures of argon and oxygen were studied as a function of oxygen percentage (0%–90%) in the discharge. The plasma was powered at 4 kW and 40 kHz at a process pressure of 5 mTorr. Al{sup +}, Al, AlO, AlO{sup +}, O{sub 2}{sup +}, O{sup +}, Al{sub 2}O{sup +}, and Ar{sup +} were among the species detected in the discharge. The deposition rate of the deposited thin film decreased with increasingmore » oxygen percentage in the discharge and results indicated that the pure gamma-alumina was obtained when the percentage of oxygen was approximately 70%. The linear plot of energy distributions of the positively charged film forming species changed from a single peak to a bimodal distribution as the percentage of oxygen exceeds 65%. In a log plot, however, the distributions showed multiple peaks ranging from 2 eV to 78 eV. Fluctuations of about 1 eV in peak energies were observed.« less