Titanium silicidation by halogen lamp annealing

Abstract

Silicidation of titanium (Ti) thin films sputter-deposited onto silicon (Si) was performed by the halogen lamp annealing method. This method was found to be quite effective in forming oxide-free and homogeneous titanium disilicide (TiSi2). Temperature dependence of silicidation was investigated by using Rutherford backscattering spectroscopy, x-ray diffraction, and sheet resistance measurements. It was found that the dominant crystal phase of silicide formed during annealing at 600 and 625 °C for 90 sec was titanium monosilicide (TiSi), and that a homogeneous TiSi2 with resistivity of ∼15 μΩ cm was formed at 700 °C. Self-aligned TiSi2 with low resistivity can be obtained with two-step annealing: the first-step annealing was carried out below 600 °C and followed by removal of unreacted Ti on silicon dioxide (SiO2), and the second-step annealing was carried out above 650 °C.