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Plasma- and gas-surface interactions during the chemical vapor deposition of tungsten from H/sub 2//WF/sub 6/

Journal Article · · J. Appl. Phys.; (United States)
DOI:https://doi.org/10.1063/1.341254· OSTI ID:6936652

Ion and neutral species were sampled from a H/sub 2//WF/sub 6/ tungsten deposition atmosphere (with and without plasma enhancement) by a line-of-sight quadrupole mass spectrometer and cylindrical mirror ion energy analyzer. These diagnostics were used to investigate the influence of neutral and ion flux on the resistivity and morphology of ..cap alpha..- and ..beta..-tungsten films. In all depositions, WF, WF/sub 2/, and WF/sub 6/ were the principle tungsten-fluorine species while WF/sup +//sub 5/ was the primary plasma-generated ion. Variation of ..cap alpha..-tungsten film properties with thickness was dominated by impurities and defects incorporated early in the deposition and by domain size. Plasma-enhanced chemical vapor-deposited films exhibited lower resistivity, and higher temperature coefficient of resistivity and domain size compared to low-pressure chemical vapor deposition films. The variation of ..cap alpha..-tungsten properties with increasing ion-bombardment energies was consistent with enhanced sputtering and damage production. Low-resistivity small-domain films were deposited at low frequencies while low-energy high-current bombardment conditions were conducive to domain growth. Nucleation and growth of ..beta.. tungsten required oxygen rather than fluorine impurities.

Research Organization:
University of California, Berkeley, California 94720
OSTI ID:
6936652
Journal Information:
J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 64:9; ISSN JAPIA
Country of Publication:
United States
Language:
English