SIMS Depth Profiling of Delta-doped Layers in Silicon

Abstract

Boron and germanium 6-doped silicon samples were studied using SIMS depth profiling on a Cameca IMS-4F instrument with O 2 + , N 2 + and Cs + primary beams at various energies and incidence angles. The depth resolution characteristics were compared. We show that, with experimental conditions being the same, the N 2 + primary beam provides for better decay lengths, while the leading edges of the profiles turn out to be significantly broadened because of the beam-induced roughness which develops at an early stage of silicon bombardment by N 2 + ions. The influence of ripple-like roughness on the SIMS profile shape is considered within the present simple analytical model. The effect of a modified layer on the SIMS profile depth was experimentally investigated. For profiles obtained with an N 2 + primary beam, it was shown that swelling of the modified layer produced by the implantation and trapping of primary particles shifts the profile as a whole toward the surface.