AVS 51st International Symposium
    Thin Films Tuesday Sessions
       Session TF2-TuM

Paper TF2-TuM7
Atomic Layer Deposition of Tungsten Disulphide Solid Lubricant Coatings

Tuesday, November 16, 2004, 10:20 am, Room 303C

Session: ALD and Applications
Presenter: T.M. Mayer, Sandia National Laboratories
Authors: T.M. Mayer, Sandia National Laboratories
T.W. Scharf, Sandia National Laboratories
S.V. Prasad, Sandia National Laboratories
R.S. Goeke, Sandia National Laboratories
M.T. Dugger, Sandia National Laboratories
Correspondent: Click to Email
We have developed a new process for the deposition of polycrystalline tungsten disulphide (WS@sub 2@) solid lubricant coatings with monolayer precision by atomic layer deposition. Sequential reactions of WF@sub 6@ and H@sub 2@S in a viscous flow reactor at 1 to 2 torr and 300 to 400°C lead to growth rates of 0.1 to 0.2 nm/cycle. Nucleation of WS@sub 2@ is impeded on SiO@sub 2@ substrates such that no growth is observed even after 200 cycles. However nucleation occurs readily on ZnO and ZnS substrates and growth catalyzed by the presence of small quantities of Zn, which segregates to the surface of the growing film. SEM with EDS, and Raman spectroscopy determined the coating morphology, composition, and crystallinity, respectively. The friction coefficient was determined to be approx. 0.12 as deposited and decreased to approx. 0.04 when the coating was annealed, well within the acceptable range of other solid lubricant coatings like sputtered MoS@sub 2@ and pulsed laser deposited WS@sub 2@, making this material and process attractive for applications in micromachine technology.