Process for formation of epitaxial cobalt silicide and shallow junction of silicon

Abstract

Abstract A process for the formation of a planar epitaxial cobalt silicide and for the formation of shallow conformal junctions for use in semiconductor processing. A cobalt silicide and titanium nitride bilayer is formed. The titanium nitride layer is chemically removed. Ions with or without a dopant are then implanted into the cobalt silicide layer. During the ion implantation, at least a portion of the cobalt silicide layer is transformed into an amorphous cobalt silicon mixture while the non-amorphous portion remains single crystal. If the ion implantation contains dopants, then after the implantation is completed, both the amorphous and non-amorphous portions of the cobalt silicide layer contain the dopants. The substrate is then annealed in either an ambient comprising a nitrogen gas or in an oxidizing ambient. During the anneal, the amorphous portion of the silicon substrate recrystallizes into a single crystal cobalt silicide layer. If the cobalt silicide layer after the ion implantation contain dopants, then during the anneal the dopants are driven out of the cobalt silicide layer and diffuse into the silicon substrate to form a conformal shallow junction. The resulting structure can be used in the vertical integration of microelectronic devices. In other words, the resulting structure is suitable for growing selective epitaxial silicon, for growing epitaxial insulators, for processing devices above the silicide in that epitaxial silicon, and for processing devices with buried conductors.

Inventors

• 👤 M. Lawrence A. Dass
• 👤 Peng Cheng
• 👤 David B. Fraser

Bibliographic Details