Cross‐sectional transmission electron microscopy investigation of Ti/Si reaction on phosphorus‐doped polycrystalline silicon gate

摘要

Titanium interaction with phosphorus‐doped polycrystalline silicon gate electrodes was investigated by cross‐sectional transmission electron microscopy and correlated with sheet resistance measurements. Phosphorus concentration above 1×1016 ion/cm2 in the polycrystalline silicon leads to decreased TiSi2 formation, discontinuous metal silicide layer, and increased sheet resistance. A possible cause could be the formation of titanium phosphide at high phosphorus concentration in the polycrystalline silicon, competing with the total titanium available for silicide formation.