AVS 45th International Symposium
    Thin Films Division Thursday Sessions
       Session TF-ThA

Paper TF-ThA10
Advances in the Characterization of Thin (<30 nm) TiN Films Using SIMS

Thursday, November 5, 1998, 5:00 pm, Room 310

Session: Ex-situ Characterization of Thin Films
Presenter: A.V. Li-Fatou, Charles Evans & Associates
Authors: A.V. Li-Fatou, Charles Evans & Associates
G.R. Mount, Charles Evans & Associates
V.K.F. Chia, Charles Evans & Associates
Correspondent: Click to Email
Titanium and titanium nitride films are widely used as barrier stacks to prevent junction spiking. It is also an important material for anti-reflection coatings (ARCs) on aluminum films to facilitate lithography processes during multilevel metallization for the manufacture of integrated circuits on silicon-based semiconductor devices. SIMS (secondary ion mass spectrometry) is a very capable tool for characterizing films because of its excellent detection sensitivities for transition elements and atmospherics. However, as films become thinner (<30 nm) quantitative analysis by SIMS also becomes more challenging. This is because a larger fraction of the film is now located in the transient region of the depth profile where the ion yields are not yet constant. In this paper we describe the effects of various analytical conditions (primary beam energies, incidence angles, and oxygen flooding using quandrupole and magnetic sector mass spectrometers) on the sputter rate at the near-surface and ion yields at the film/substrate interface. The samples used in this study were CVD grown samples of Ti (10 nm) /Si and Ti (3x10 nm)/Si. Our preliminary study shows that oblique angle bombardment with oxygen flooding can result in both accurate quantification and depth calibration in the upper 15 nm of the sample; there appears to be a dependence between the incidence angle and the primary beam energy. Interfacial mixing is reduced by using a lower primary beam energy. Ion yield enhancements are reduced using oblique incidence bombardment and oxygen flooding. Difficulties still exist when using SIMS to determine the exact the film thickness.