TEM study of metallic contacts to nanostructured silicon

Different metals were deposited onto the surface of porous silicon in order to carry on a comparative morphological and electrical study of the result ing metal/porous silicon interfaces. We have used gold, aluminum and titani um (as deposited and annealed) as metal contacts. In order to perform Trans mission Electron Microscopy (TEM) characterization. cross-section samples w ere prepared. It has been observed that gold and titanium contacts to porou s silicon become clustered, while aluminum tends to diffuse into the PS lay er. However, in the case of titanium (annealed) contacts, there exists a gr adual transition between the metallic and the porous silicon layers. Furthe rmore, we have attempted to establish a relationship between the different morphologies obtained from the deposition of various metals onto porous sil icon and the values of the series resistance of the different metal/porous silicon/Si structures, obtained from current-voltage measurements. In the c ase of titanium contacts, subjected to rapid thermal processing, a very low value of the series resistance has been obtained. (C)1999 Acta Metallurgic a Inc.