Remote-plasma chemical vapor deposition of conformal ZrB2 films at low temperature:: A promising diffusion barrier for ultralarge scale integrated electronics

High-quality ZrB2 thin films have been deposited at substrate temperatures as low as 300 degreesC by a new method: remote hydrogen-plasma chemical vapor deposition from the single-source precursor Zr(BH4)(4). Carrying out the deposition in the presence of atomic hydrogen generates films with properties that are far superior to those deposited by purely thermal methods; the latter are boron-rich, oxidize readily in air, and adhere poorly to the substrates. In contrast, the films generated at a substrate temperature of 300 degreesC in the presence of atomic H have a B/Zr ratio of 2, a resistivity of 40 muOmega cm, an oxygen content of less than or equal to4 at. %, and are fully conformal in deep vias. A 20 nm thick amorphous film of ZrB2 on c-Si(001) prevents Cu indiffusion after 30 min at 750 degreesC. We propose that the beneficial effects of atomic hydrogen can be attributed to promoting the desorption of diborane from the growth surface. (C) 2002 American Institute of Physics.