Simultaneous Formation of TiN and TiSi2 by Rapid Lamp Annealing in NH3 Ambient for VLSI Contacts

The bilayer of self-aligned TiN/TiSi2 was formed by the lamp annealing in N2 or NH3, simultaneously. Thickness ratio TiN/TiSi was able to be controled by the condition of annealing temperature and/or annealing ambient (N2, NH3); by the annealing in NH3 at lower temperature, the relatively thicker TiN layer was formed. Chemical stability and the electrical characteristics of the AlSi/TiN/TiSi2/n+Si contact system were studied. It was found that the bilayer of TiN/TiSi2 formed by the lamp annealing had good chemical stability in HF, low contact resistance to n+Si, and the good barrier effect on Al diffusion.