Surface roughness-induced artifacts in secondary ion mass spectrometry depth profiling and a simple technique to smooth the surface

We report on secondary ion mass spectrometry (SIMS) depth profile artifacts induced by surface roughness. The formation of a TiSi2 film at 800 degrees C on a boron doping superlattice (DSL) of Si results in a rough (22.0 nm root mean square) interface between the film and Si DSL. After chemically etching off the TiSi2 him, SIMS information is collected while sputtering through the surface of the Si DSL. The resulting depth profiles are irreproducible due to the initial surface roughness. By chemo-mechanically polishing the Si prior to SIMS analysis, we smooth the surface and the resulting depth profiles are then consistent and easily explained by current diffusion theory. (C) 1996 American Vacuum Society.