PROPERTIES OF IRON SILICIDE CONTACTS TO N-TYPE AND P-TYPE SILICON

Thin polycrystalline films of FeSi and beta-FeSi2 were formed by solid state reaction with either boron or phosphorus doped silicon. The cor responding electrical heterojunction properties were studied by temper ature activated current-voltage and capacitance-voltage analysis. The FeSi/Si Schottky characteristics showed that the current transport mec hanism was dominated by thermionic emission across the interfaces for both n- and p-type silicon substrates. Indications of recombination th rough deep levels was only detected for n-type silicon measured by cur rent-voltage at low temperatures. The Schottky barrier heights of FeSi were estimated to 0.68 +/- 0.03eV and 0.40 +/- 0.03eV at 0K for respe ctively n- and p-type silicon. The Schottky barrier was observed to be pinned to the silicon valence band. The formation of beta-FeSi2 produ ced current transport characteristics with ideality factors of about 1 .02-1.05 on both n- and p-type silicon indicating no recombination thr ough deep levels inside the silicon depletion layer. The CV results on p-type silicon strongly showed the presence of shallow defects or neu tral complex formation.