Sensor for measuring the atomic fraction in highly dissociated hydrogen

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Description

Atomic hydrogen is a very important constituent for processes ranging from cleaning oxide from GaAs and annealing amorphous silicon to the deposition of diamond. Because the usual techniques for measuring atomic fraction are either expensive and cumbersome to use, or unsuitable for application to highly dissociated hydrogen, a specially designed sensor was developed. Sensor design is based on a diffusion tube with noncatalytic walls, having one end open to the atom source and a catalytic closure at the other end. The sensor is simple and inexpensive to fabricate, and determining atom density is straightforward. Sensor design also inhibits thermal runaway, ... continued below

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16 p.

Creation Information

Gardner, W.L. December 31, 1994.

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Description

Atomic hydrogen is a very important constituent for processes ranging from cleaning oxide from GaAs and annealing amorphous silicon to the deposition of diamond. Because the usual techniques for measuring atomic fraction are either expensive and cumbersome to use, or unsuitable for application to highly dissociated hydrogen, a specially designed sensor was developed. Sensor design is based on a diffusion tube with noncatalytic walls, having one end open to the atom source and a catalytic closure at the other end. The sensor is simple and inexpensive to fabricate, and determining atom density is straightforward. Sensor design also inhibits thermal runaway, which occurs when atom density is high enough to impart enough recombination energy to the non-catalytic surface to substantially raise its temperature. While recombination coefficients for such surfaces are very low near room temperature, they increase nearly exponentially with temperature unless actively cooled. With the use of a straightforward calibration scheme to determine the variation in species fraction along the diffusion tube, the atomic fraction at the tube opening is determined. Design strategy, implementation considerations, and calibration method are presented. In addition, data obtained from an atomic hydrogen source are compared to relevant published data.

Physical Description

16 p.

Notes

OSTI as DE95006531

Source

  • 41. annual American Vacuum Society symposium, Denver, CO (United States), 24-28 Oct 1994

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  • Other: DE95006531
  • Report No.: CONF-941001--13
  • Grant Number: AC05-84OR21400
  • DOI: 10.2172/28342 | External Link
  • Office of Scientific & Technical Information Report Number: 28342
  • Archival Resource Key: ark:/67531/metadc672041

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  • December 31, 1994

Added to The UNT Digital Library

  • June 29, 2015, 9:42 p.m.

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  • Jan. 22, 2016, 4:33 p.m.

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Gardner, W.L. Sensor for measuring the atomic fraction in highly dissociated hydrogen, report, December 31, 1994; Tennessee. (digital.library.unt.edu/ark:/67531/metadc672041/: accessed August 20, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.