IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Friday Sessions
       Session EL-FrM

Paper EL-FrM10
Low-Temperature CVD of ZrB2 and CrB2 Metallic Ceramic Thin Films

Friday, November 2, 2001, 11:20 am, Room 124

Session: ULSI Metallization & Interconnects
Presenter: E.J. Klein, University of Illinois at Urbana-Champaign
Authors: E.J. Klein, University of Illinois at Urbana-Champaign
D.-Y. Kim, University of Illinois at Urbana-Champaign
G.K. Windler, University of Illinois at Urbana-Champaign
J.-H. Sung, Novellus
D.M. Goedde, Intel
G.S. Girolami, University of Illinois at Urbana-Champaign
J.R. Abelson, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
Transition metal diborides are classified as "metallic ceramics" due to their high mechanical hardness, chemical stability, melting temperature and electrical conductivity. This combination of properties makes them attractive as diffusion barrier materials for the contact metallization in next-generation microelectronics or wide bandgap semiconductors. We report the low-temperature chemical vapor deposition of fully conformal ZrB2 and CrB2 thin films with essentially bulk properties. ZrB2 films are deposited at a substrate temperature of 300 C using the single-source precursor Zr(BH4)4 and a concurrent flux of atomic hydrogen produced by a remote hydrogen plasma source. The films have a B/Zr ratio of 2, electrical resistivity of 40 micro-ohm-cm, and appear amorphous in X-ray diffraction. By contrast, films grown without the use of atomic hydrogen are B-rich, oxidize rapidly in air, and have high resistivity; we will show using mass spectroscopy that the role of atomic hydrogen is to enhance the removal of excess boron from the growth surface as B2H6. A 20 nm thick stoichiometric ZrB2 film deposited onto doped c-Si(001) has a low contact resistivity and is an excellent diffusion barrier: a Cu film deposited by PVD onto the ZrB2 does not interdiffuse with Si after annealing for 30 minutes at 750 C. CrB2 is deposited by CVD at 300 C without atomic hydrogen using the new precursor Cr(B3H8)2, which we synthesized in our laboratories and report for the first time. We will report preliminary results on the composition, electrical, and diffusion barrier properties of CrB2 films.