TEM analysis of TiSi2 on Si and polysilicon
TiSi2, when deposited on poly-Si and Si, exhibits very low sheet resistance ana can be easily integrated into existing device and IC fabrication environments. However, the high temperature process stability of TiSi2 is rather limited. The silicide must be able to withstand processing temperatures in the 800°C-1000°C range for the fabrication of many high voltage devices and integrated circuits. In the present investigation the high temperature stability of the TiSi2 structures were examined using TEH on both planar and cross-sectional specimens.The starting materials in this study were <100> Si substrates doped with 1x1016 cm-3 boron. The gate SiO2 was grown and then the poly-Si deposited on the substrate followed by TiSi2 formation on the poly-Si, creating an actual MOS structure used for device fabrication. The TiSi2 was formed by rf sputtering of Ti followed by either a two-step thermal or rapid thermal anneal (RTA) to form the silicide.