Dopant control of metal silicide formation

A metal silicide-silicon structure, including:

• a first silicon region which is undoped or doped to a level less than about 10.sup.18 atoms/cm.sup.3,
• a second silicon region containing a selected dopant in an amount at least about 10.sup.18 atoms/cm.sup.3,
• metal silicides simultaneously thermally formed with said first and second silicon regions, said metal silicides in said first and second regions being comprised of the same metal, and having a different stoichiometry, where the stoichiometry is dependent upon the dopant and doping level of said silicon regions.

A metal silicide-silicon structure, including:

• a first doped silicon substrate region and a second undoped silicon substrate region,
• a layer of metal silicide formed by thermal conversion of a metal deposited on said first and second silicon substrate regions, said metal silicide being formed on both said doped and undoped silicon regions, said metal silicide being substantially comprised of a single metal constituent,
• wherein the dopant in said doped silicon region and its concentration are such that the temperature ranges of formation of at least two metal silicide compound phases are shifted during said thermal conversion, to produce a silicide compound phase on said doped silicon substrate region that is not present in the metal silicide formed on said undoped substrate region.

A metal silicide-silicon structure, including:

• a first doped silicon substrate region including a selected dopant in an amount sufficient to affect the phase of a metal silicide thermally formed on said first region,
• a second silicon substrate region doped to a level insufficient to affect the phase of a metal silicide thermally formed on said second region,
• a metal silicide simultaneously thermally formed on both said first and second regions and containing the same metal, the compound phase of said metal silicide formed in said first region being different than the compound phase formed in said second region.