INTERFACIAL ELECTRICAL-PROPERTIES OF ELECTROLESS NI CONTACTS FORMED USING SELF-ASSEMBLING MONOLAYERS ON SILICON

A new, additive, substrate metallization process, useful for high reso lution lithography and microelectronic circuit fabrication has been de veloped. The process, which involves surface modification with a self- assembled monolayer (SAM) film, selective binding of a catalytic Pd co lloid, and electroless (EL) metal deposition, was used to deposit EL N i on p-type (100) silicon substrates with a native oxide layer. The de posits were characterized by current-potential (I-V) and capacitance-p otential (C-V) measurements. and were compared to evaporatively deposi ted Ni films. Schottky barrier heights for both the EL and evaporated Wi contacts ranged between 0.6 to 0.7 eV; similar to 0.1 to 0.2 eV hig her than the typical value for Wi on atomically clean p-type silicon, as expected for contacts separated from the substrate by a thin insula ting layer. The similarity of the EL and evaporated Ni barrier heights indicates that the buried organic SAM film and the Pd catalyst did no t significantly alter the interfacial electrical characteristics. Heat ing the EL Ni deposits to over 300 degrees C reduced the Schottky barr ier height and increased the leakage current, although less so than on the evaporated contacts.