Ni-Silicide/Si and SiGe(C) Contact Technology for ULSI Applications

We have investigated the crystalline and electrical properties of Ni silicide/Si and SiGeC contacts for ULSI applications. NiSi/Si contacts promises the contact resistivity as low as 10^-8 Omegacm² for both n+- and p+-Si. Degradation of the sheet resistance of NiSi layers critically depends on the annealing time particularly at temperatures ranging from 650degC to 750degC. The enlargement of the Si-exposed region concomitant with the NiSi agglomeration is a dominant factor responsible for the increase in sheet resistance and the activation energy of this process is estimated to be 2.8plusmn0.4 eV. Incorporation of Ge into Ni/Si systems is effective in raising the transformation temperature from NiSi to NiSi₂. Incorporation of C into NiSi/Si system effectively suppresses the NiSi agglomeration. C introduction also causes the pile-up of B atoms at the NiSi/Si interface, which promises the reduction of the contact resistivity