Sub-Micron Mesotaxial CoSi2 Wires

Abstract

ABSTRACTTransition metal suicides are receiving an increasing amount of attention as materials for VLSI interconnects because of their low resistivities and ease of integration with silicon. A recently invented technique, mesotaxy, allows the production of buried single-crystal suicide layers in silicon.Buried suicide layers made by implantation into (100) Si wafers can be patterned by restricting the implant with an oxide mask, giving great flexibility in the types of features that can be produced. We have fabricated simple microstructures to investigate the formation and properties of mesotaxial CoSi2. Wires of constant dose but varying widths exhibit a transition in morphology from {111} faceted wires to largely (100) faceted layers. After annealing for prolonged periods, the finer wires show the effects of coarsening. We have also observed the movement of a significant amount of Co from the oxide implant mask into the substrate during these anneals. The wires show greatly improved thermal stability compared to polycrystalline suicides formed by deposition.1