Properties of a-C : H coatings prepared by PECVD for laser fusion targets

Amorphous hydrogenated carbon films are the nominal ablators to be used in French inertial confinement fusion (ICF) experiments. These targets are dev eloped for the future Megajoule laser (LMJ) of the CEA. Coatings are prepar ed by remote rf-PECVD and their properties have been investigated. Laser fu sion targets must have optimized optical characteristics (UV-visible transp arency), mechanical strength, high gas permeability, low oxygen pollution. The films are characterized by C-13 NMR, RES, UV-visible spectroscopy, gas permeation, thermogravimetric analysis. A study of the glow discharge is al so developed using optical emission spectroscopy and mass spectrometry. In this article, we try to understand the relationships between precursors, pl asma composition, deposition rate and film properties. Best results are obt ained with trans-2-butene/hydrogen (T2B/H-2) coatings in post-discharge.