Progress Update on CVD of Beryllium

Capsules with beryllium ablators are very important targets for the DOE National Ignition Facility (NIF) laser in the Inertial Confinement Fusion Program. Two leading candidates for fabricating beryllium capsules are the machining and bonding of hemispheres, and physical vapor deposition of beryllium onto plastic or other shells. An attractive possibility would be to coat a spherical mandrel with a thin layer of beryllium by a non-line-of-sight process. This coating could be applied via the chemical vapor deposition (CVD) of beryllium. Our first attempt at coating beryllium via CVD was done by using bis(cyclopentadienyl)beryllium, (C₅H₅)₂Be, as the precursor material. Results obtained by use of (C₅H₅)₂Be as the precursor material is discussed. However, difficulties we encountered with use of the (C₅H₅)₂Be precursor material led us to examine a relatively unexplored area of beryllium chemistry, namely that of its amines. This redirection also led us to change surrogate material for use in the developmental work.