Silicon Carbon-Nitride (SiCxNy:H) by High Target Utilisation System (HiTUS) for crystalline silicon solar cell anti-reflective coating and passivation

SiCxNy:H films were deposited as anti-reflective (ARC)– passivation layers on crystalline silicon photovoltaics. The thin films were deposited using a remote plasma sputtering system HiTUS (High Target Utilisation Sputtering). The HiTUS allows the deposition of SiCxNy:H avoiding the use of pyrophoric silane precursor. Minority carrier lifetime was monitored, the effective minority carrier lifetime increased up to 40.7 µs, which corresponds to an implied Voc of 640mV. Film roughness and thickness of the films were measured using coherence correlation interferometry (CCI) using a Taylor Hobson “Sunstar”. Deposited films were found to have rms roughness values below 2nm and the film roughness was found to be proportional to passivation quality but inversely proportional to deposition rates. Films were also characterised using Horiba UVISEL spectroscopic ellipsometer, which provided refractive index dispersion. The deposited films exhibited refractive indexes in the range of 2-2.5. Measured deposition rates were in range 1-25nm/min.