Specific Contact Resistivity Measurement by a Vertical Kelvin Test Structure

Abstract-A vertical Kelvin test structure is used to measure tln 2 spe-cific contact resistivity of the A1 (1-percent Si) /Si and A1 ( 1-PC rcent Si)/TiSi,/Si contact system. For the vertical test structure, the driv-ing current flows “vertically, ” thus the current crowdings and sheet resistance effects are eliminated and measurement on the true specific contact resistivity becomes possible. Experimental works show that re-sults obtained by using this vertical structure are closer to the true specific contact resistivities than those obtained by using the conven-tional six-terminal Kelvin method. It is also found that Rsd, the sheet resistance directly underneath the contact pad, is much less thall that of the conduction bar without the contact pad. A value of (1.17 f 0.17) X SZ. cm2 specific contact resistivity is obtained fcr the A1 ( 1-percent Si) /TiSi2 ( direct reaction) /Si system. I