Comparison Between P-Type Dopants For Shallow Junction Formation By Diffusion From An Ion-Implanted Silicide

The ability and advantages of a process in which junctions are formed by diffusion from an implanted silicide were shown before. However, part of the B-dose penetrates through a CoSi 2 -layer of 100 nm and therefore the heavier BF 2 is investigated in this work. It will be shown that excellent profiles in the Si can be obtained with an RTP-diffusion step. In the case of TiSi 2 , both BF 2 and Ga are considered as alternatives. Our results indicate that Ga in combination with an RTP-diffusion step yields the best result. On the other hand, the classical furnace treatments resulted in a pronounced TiGa compound formation which limits the available dose for diffusion into the Si. BF 2 is not likely to be used at all with TiSi 2 because of metal-dopant and metal-fluorine compound formation.