BARRIER-HEIGHT NONUNIFORMITIES OF PTSI SI(111) SCHOTTKY DIODES/

The forward current-voltage characteristics of PtSi Schottky contacts on epitaxial n-type Si (111) is studied in the temperature range from 100 to 300 K. A current contribution in excess to that predicted by th ermionic emission-diffusion theory is caused by a few thousand patches of reduced Schottky barrier height in a device area of 3.14 mm(2). Th e typical lateral extent of these patches is 70-250 nm. It correlates with the size of surface bumps observed. The number of patches is redu ced upon increasing the silicidation temperature up to T-sil = 550 deg rees C. Possible non-uniformities of the typical crystallite grain siz e of 20 nm are not resolved due to effective pinch-off.