A New Method for Silicide Patterning based on Local Oxidation

A novel method for silicide patterning is presented. Continuous epitaxial CoSi2 surface layers on Si(100) were capped with an SiO2/Si3N4-oxidation mask with a line width of 1.5 ¿m and subsequently thermally oxidized. During oxidation the silicide lines are pushed into the substrate in the unprotected regions preserving their stoichiometry, morphology and even their single crystallinity. At a critical oxide thickness the contiuous silicide layer disrupts exactly at the edges of the oxidation mask and the oxidized regions of the silicide become separated from the unoxidized regions. In this way buried interconnects and metallized silicon mesa structures can be obtained. The method should be applicable also to polycrystalline silicides, such as TiSi2.