MARKER AND RADIOACTIVE SILICON TRACER STUDIES OF PTSI FORMATION

Marker and radioactive Si-31 experiments have been performed to investigate atomic diffusion during PtSi formation. The marker work used a thin metallic layer (Ti, Co, Ni) as a marker. Analysis of the marker displacement indicated growth dominated by silicon diffusion (approximately 90%). The interpretation of data from the radioactive tracer experiments is less clear cut. However, when examined in conjunction with the marker results, it would appear that either PtSi growth took place by silicon substitutional diffusion or by a mixed interstitial mechanism (i.e., a mixture of interstitial and interstitialcy diffusion). Arguments are presented to suggest that silicon vacancy diffusion during silicide growth is the most likely mechanism. This interpretation is found to be generally consistent with other recently published work on PtSi formation.