SIMS study of depth profiles of delta-doped boron/silicon alternating layers by low-energy ion beams

Most recently, the semiconductor industry has been making use of low-energy ion implantation for shallow junction. It requires less than 1 nm depth resolution to evaluate the junction profile. We have started the research to develop the international standard respect to the depth profile of shallow junction in Japan. In this study, we originally made the delta-doped B (0.02 nm)/Si (20 nm) alternative layers on a silicon substrate by using high-vacuum magnetron sputter deposition instrument and evaluated the depth resolution to make use of low-energy oxygen ion beam from 0.25 to 2 keV. The higher depth resolution was given, the lower oxygen ion beam energy was performed. However, the depth resolution was made drastically worse when the ion beam with the accelerating energy of less than 0.5 keV was used. We use MRI model to extract the depth resolution parameters (atomic mixing and roughness). The factors, which make the depth resolution worse, are discussed.