Effects of deposition rate on the encroachment in tungsten films reduced by H2

1573-4803

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract The deposition rate of tungsten selectively prepared by hydrogen reduction of WF6 was measured, and the encroachment produced by inherent silicon reduction even in the presence of H2 gas was examined by cross-sectional TEM and SEM. In the WF6-H2 system, the degree of encroachment is not explained by the Si reduction reaction alone, but is rather related to the Si reduction time decreasing with increasing deposition rate of H2-reduced tungsten film, because a blocking layer is formed above the Si-reduced tungsten. This results in a lesser degree of encroachment. Consequently a high deposition rate of H2-reduced tungsten can decrease the degree of encroachment. By calculation, a thickness of 6.8–13.3 nm is necessary for H2-reduced tungsten to prevent WF6 gas from reacting with Si.

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