Ni silicide formation on polycrystalline SiGe and SiGeC layers

The reactions of Ni with polycrystalline Si, Si0.82Ge0.18 and Si0.818Ge0.18C0.002 films in two different configurations during rapid thermal processing were studied. For the usually studied planar configuration with 20 nm thick Ni on 130-290 nm thick Si1-x-yGexCy, NiSi1-xGex(C) forms at 450degreesC on either Si0.82Ge0.18 or Si0.818Ge0.18C0.002, comparable to NiSi formed on Si. However, the agglomeration of NiSi1-xGex(C) on Si0.818Ge0.18C0.002 occurs at 625degreesC, about 50degreesC higher than that of NiSi1-xGex on Si0.82Ge0.18. For thin-film lateral diffusion couples, a 200-nm thick Ni film was in contact with 80-130 nm thick Si1-x-yGexCy through 1-10 mum sized contact openings in a 170 nm thick SiO2 isolation. While the Ni3Si phase was formed for both the Si0.82Ge0.18 and Si0.818Ge0.19C0.002 samples, the presence of 0.2 at.% C caused a slightly slower lateral growth.