Buried Cobalt Silicide Layers in Silicon Created by Wafer Bonding

Abstract

A buried conductive layer in silicon has been created using wafer bonding technique, with a cobalt interfacial layer. Co‐coated silicon wafers were brought into contact with either similar or uncoated wafers at room temperature. was then formed through a solid‐phase reaction, during an anneal at 700 to 900°C. A 700 Å buried , with a resistivity of approximately 21 μΩ cm, was achieved. Good adhesion, as measured by tensile strength testing, between the wafers was achieved. Transmission electron microscopic investigations (Co‐coated wafer bonded to bare silicon) showed that the silicide has not grown into the opposite wafer, and that an amorphous layer exists between the silicide and the silicon surface. The presence of such a layer has been confirmed by electrical characterization.