Characterization of titanium silicide by Raman spectroscopy for submicron IC processing

The formation of the low resistivity C54 phase of titanium silicide (TiSi₂) used in submicron IC technology was studied using Raman spectroscopy. TiSi₂ on both pad areas (100 X 100 μm₂) as well as polycrystalline and amorphous silicon narrow lines (line widths: 0.35 to 1.0 μm) were formed under various rapid thermal annealing temperatures. The results showed that Raman spectroscopy could accurately identify the temperature ranges of the formation, transformation and agglomeration of TiSi₂. Qualitative analysis confirmed the difficulty of forming C54 phase TiSi₂ on narrow polycrystalline lines. TiSi₂ was also found to form at a lower annealing temperature on amorphous Si than on polycrystalline Si, which is attributed to the random nature of amorphous Si, although its degradation also occurs earlier. These results demonstrate the applicability of Raman spectroscopy for characterizing TiSi₂ used in sub-half-micron IC processing. 1998 Published by Elsevier Science B.V. All rights reserved.