Low-resistance submicrometer contacts to silicon

The fabrication of submicrometer contacts of Al, PtSi, TiN, and CVD W to both arsenic- and boron-doped junctions using e-beam lithography and photolithography in a mix-and-match mode is described. The contact resistances obtained indicate that this will not be a major barrier for future ULSI scaling. The measured resistance values are compared to those obtained using a 2-D model and the discrepancies are discussed. A generalized scaling law for electromigration at contacts is also developed by taking into account the current distribution in the contact area