AVS 45th International Symposium
    Thin Films Division Wednesday Sessions
       Session TF-WeM

Paper TF-WeM5
Low Temperature Deposition of Zirconium Diboride, A Candidate Diffusion Barrier, Using Remote Plasma CVD

Wednesday, November 4, 1998, 9:40 am, Room 310

Session: ULSI Metalization and Interconnects
Presenter: J.H. Sung, University of Illinois, Urbana-Champaign
Authors: J.H. Sung, University of Illinois, Urbana-Champaign
D.M. Goedde, University of Illinois, Urbana-Champaign
G.S. Girolami, University of Illinois, Urbana-Champaign
J.R. Abelson, University of Illinois, Urbana-Champaign
Correspondent: Click to Email
Zirconium diboride is potentially suitable as an advanced diffusion barrier in ULSI circuits because of its low electrical resistivity, 10 micro-ohm-cm in bulk form, very high melting temperature, ~ 3000 C, and resistance to air oxidation and reaction with metals. However, the CVD of ZrB2 from conventional halide/hydrogen source gases requires a relatively high temperature of ~ 900 °C. We showed that zirconium tetrahydroborate, Zr(BH@sub 4@)@sub 4@, is an attractive precursor which has high vapor pressure and can be thermolyzed at < 300 °C to produce ZrB2 films with resistivity ~ 120 µm@OMEGA@-cm. In this work, we report the use of remote plasma CVD to further reduce the ZrB2 deposition temperature and improve the film properties. Atomic hydrogen is generated by a microwave plasma source and mixed downstream with Zr(BH@sub 4@)@sub 4@ to produce high quality films at only 150 °C. The films have resistivity ~ 60 µm@OMEGA@-cm, and low carbon and oxygen contamination. XPS data indicate that the plasma-deposited films are single phase ZrB2. Based on in-situ mass spectroscopy data, we will present a preliminary analysis of the chemical reaction pathways associated with the remote plasma growth process.