Magnetron Sputtering of Boron-Doped Tungsten Thin Films for ICF Applications

Boron-doped tungsten (W) films are of interest in inertial confinement fusion (ICF) experiments for enabling radiochemical diagnostics. ¹⁰B-doped W inner shells may be used in double-shell capsule designs to passively detect alpha particle energy deposition via the ¹⁰B(α,n)¹³N reaction, with post-shot analysis performed using the Radiochemical Analysis of Gaseous Samples (RAGS) system at the National Ignition Facility (NIF). Shell quality (density, leak tightness, surface roughness, impurity incorporation, thin film microstructure, etc.) is of utmost importance because it directly affects the implosion dynamics leading to Rayleigh-Taylor instability.



This work investigates the use of Direct Current Magnetron Sputtering (dcMS) and High-Power Impulse Magnetron Sputtering (HiPIMS) deposition of W simultaneously with RF sputtering of B to create a dense, homogenous, and gas impermeable B doped W inner shell. Metrology results including density, microstructure, dopant concentration, and gas impermeability of resultant B doped W coatings are presented. Additionally, a procedure for characterizing the magnetic field parameters in the sputtering chamber will be investigated.