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RBS and SIMS characterization of tungsten silicide deposited by using dichlorosilane and tungsten hexafluoride
Author(s) -
Gregory Richard B.,
Lamartine Bruce C.,
Wu T. H. Tom,
Tompkins Harland G.
Publication year - 1989
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740140105
Subject(s) - dichlorosilane , tungsten , silicide , rutherford backscattering spectrometry , analytical chemistry (journal) , secondary ion mass spectrometry , chemical vapor deposition , silicon , chemistry , silanes , wafer , nuclear reaction analysis , fluorine , mass spectrometry , materials science , ion , nanotechnology , silane , organic chemistry , chromatography
Rutherford back‐scattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) were used to characterize tungsten silicide (WSi x ) which had been chemical vapor deposited using higher‐than‐normal temperatures and a new reactant. Silicon wafers were subjected to a flowing mixture of dichlorosilane (SiH 2 Cl 2 ) and tungsten hexafluoride (WF 6 ) with temperatures ranging from 450°C to 650°C. The conventional process uses SiH 4 and WF 6 with temperatures from 250°C to 400°C. RBS analysis was performed on a matrix of samples produced to show silicon‐to‐tungsten ratios as functions of various deposition temperatures and reactant gas flow ratios. The Si/W ratios obtained ranged from 2.0 to 2.8 over the 450–650°C temperature range. SIMS analysis provided the chlorine and fluorine distributions in the WSi x films, again as functions of various deposition temperatures and flow ratios. This data showed fluorine concentrations on the order of 1 × 10 16 − 4 × 10 18 cm −3 , which are far lower than those concentrations observed for the conventional WF 6 /SiH 4 chemistry (about 1 × 10 20 cm −3 ).