Formation of Silicides by Rapid Thermal Annealing Over Polycrystalline Silicon

ABSTRACTThe formation of titanium suicide over polycrystalline silicon has been investigated after rapid thermal annealing treatment in nitrogen and argon ambients. After rapid thermal annealing 300 Å thick titanium overlayer at 900°C for 10 seconds, the sheet resistance of about 3 Ω/□ was achieved, which decreased to 2 Ω/□ after 1100°C / 10s treatment. The TiSi2 Phase was found to be stable after RTA treatments up to 1100°C /10s with no or negligible migration of titanium along the grain boundaries in polycrystalline silicon. In the nitrogen ambient, an external layer (titanium rich, mixture of titanium oxide and nitride) was observed to form after the RTA treatment, but the surface was found clean in the argon ambient.