Effects of rapid thermal processing on the formation of uniform tetragonal tungsten disilicide films on Si(100) substrates

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Abstract
Thin films of tungsten silicide with resistivities of 30–35 μΩ cm have been formed by sputter depositing 710 Å of W metal onto (100)–oriented, 3–7 Ω cm, p-type silicon wafers. The samples were fast radiatively processed in a rapid thermal processing (RTP) system under high vacuum for time anneals ranging from 15–20 s at two temperatures (∼1100 and ∼1150 °C). The inevitable oxide barrier at the interface is shown to decrease with increasing RTP time and temperature, evidenced by both Auger electron spectroscopy and secondary ion mass spectrometry experiments. The high film stress produced by thermal considerations does not seem to effect the resulting resistivity and, furthermore, appears to relax at higher temperatures when the film surface becomes ‘‘buckled.’’