Boron contamination and antimony segregation at the interface of directly bonded silicon wafers

摘要

The characterization of the interface between directly bondedn‐type silicon wafers by capacitance‐voltage (C‐V) profiling, secondary‐ion mass spectrometry (SIMS), and transmission electron microscopy (TEM) is reported. At the interface a boron diffusion peak is found that can be explained by initial boron contamination of the wafer surfaces before bonding. Furthermore, the presence of an amorphous SiO0.54layer at the bonding interface is revealed by TEM and SIMS. Antimony is shown to diffuse through this layer and to segregate at the interface. Diffusion and segregation phenomena are simulated with the process simulation packagesuprem‐3andC‐Vprofiling is simulated with the device simulation packagecurry. Features in theC‐Vprofiling results are explained in terms of the observed boron contamination. The behavior of the resistivity near the interface of directly bonded silicon wafers, reported in literature, is also explained by boron contamination.