Asymmetric depth profiles of elemental and molecular secondary ions are observed during secondary ion mass spectrometry (SIMS) analyses of polycrystalline-TiN/Ti/TiN(001) trilayers using a Cs+ ion beam. The sputter-etching rate R and the secondary ion yield Y from TiN(002) layers are strongly dependent on the incidence angle of the primary ion beam. When the azimuthal angle between the incident beam and one of the in-plane <100> directions in TiN(001) is varied from 0 to 40 degrees, RTiN(001) and YTiN(001) vary by more than 40 % and by nearly a factor of three, respectively. In contrast, for polycrystalline TiN layers RpolyTiN and YpolyTiN are invariant with incident beam angle. Channeling of primary ions and secondary recoils through 0.106 nm wide channels between highly aligned (100) or (010) planes in TiN(001), and the lack of such alignment in the polycrystalline TiN are the major reasons for the observed differences.
Citation: Journal of Vacuum Science and Technology B
Issue: No. 3
Pub Type: Journals
channeling, depth profile, secondary ion mass spectrometry