Shallow Junction Formation Using MoSi2 as Diffusion Source

Arsenic and boron implanted MoSi2 layers as diffusion source for the formation of n+/p and p+/n ultra-shallow junctions, respectively, are investigated. The high arsenic diffusivity and solubility in MoSi2, as well as the favorable arsenic segregation coefficient at the silicide silicon interface, make Mo-silicide suitable as arsenic diffusion source and allow the formation of n+/p junctions as shallow as 100 nm with high surface carrier concentration. On the contrary, the low boron mobility in MoSi2, probably due to boron-molybdenum compounds, make ineffective the Mo-silicide as boron diffusion source.