Synthesis of yttrium silicates by annealing r.f. sputtered glassy coatings

In this work, the composition evolution of yttrium silicate coatings was investigated during r.f. sputtering from a γ-Y2Si2O7 compound target, focusing on the effect of Ar pressure, target-substrate distance and r.f. power. By controlling the number of collisions between Ar gas and target species, glassy coatings with the stoichiometry of Y2SiO5 and Y2Si2O7 were obtained. Finally, the formation of X2-Y2SiO5 on SiC substrates was observed after annealing the glassy coatings in air at 1250 °C. After annealing at 1550 °C γ-Y2Si2O7 crystallized with high quality and grain boundaries appeared to be crack-free.