Synthesis and mechanical properties of niobium films by ion beam assisted deposition

Book · Tue Dec 31 04:00:00 EST 1996

OSTI ID:490770

Ji, H; Was, G S; Jones, J W ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States)

Mechanical properties of niobium thin films are studied by controlling the microstructure, texture and residual stress of the films using ion beam assisted deposition (IBAD). Niobium films were deposited onto (100) Si substrates and their microstructure, texture and residual stress were measured as a function of ion energy and R ratio (ion to atom arrival rate ratio). The grain sizes of these films ranged from 20 nm to 40 nm and no effect of ion bombardment was observed. All the films have strong (110) fiber texture, but the in-plane texture is a strong function of the incident angle, energy and flux of the ion beam. Results show that while the degree of the texture increases with increasing ion energy and flux, it is also a strong linear function of the product of the two. The residual stress of the films was measured by a scanning-laser reflection technique. As a function of normalized energy, the stress is tensile for En < 30 eV/atom with a maximum of 400 MPa at about 15 eV/atom. It becomes compressive with increasing normalized energy and saturates at {minus}400 MPa for En > 50 eV/atom. Both PVD (physical vapor deposition) and IBAD films have a hardness of about 6 GPa at shallow depth measured by nanoindentation. The different stress state may be responsible for the 15% difference on hardness observed between the PVD and IBAD films.

• Sponsoring Organization: National Science Foundation, Washington, DC (United States)
• OSTI ID: 490770
• Report Number(s): CONF-960401--; ISBN 1-55899-337-1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ENERGY BEAM DEPOSITION
EXPERIMENTAL DATA
GRAIN SIZE
HARDNESS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NIOBIUM
RESIDUAL STRESSES
SYNTHESIS
TEXTURE
THIN FILMS
YIELD STRENGTH