Liquid phase epitaxy of yttrium aluminum garnet: Reduction of growth rate by germanium oxide

Germanium is found to be a growth inhibitor in the liquid phase epitaxy of yttrium aluminum garnet. Germanium oxide additions to PbO/B₂O₃ fluxed melts for the liquid phase epitaxy of Y₃Al₅O₁₂ and Ce:Y₃Al₅O₁₂ on Y₃Al₅O₁₂ substrates reduce the epitaxial growth rate in an effect similar to that with calcium oxide additions to melts for the growth of Y₃Fe₅O₁₂. In contrast, cerium oxide additions to Y₃Al₅O₁₂ melts have no measurable effect on growth rate. Germanium oxide additions reduce the growth rate sensitivity with supercooling, at saturation temperatures near 900 °C, as an essentially linear decreasing function of the germanium oxide concentration, GeO₂/(GeO₂+2Al₂O₃), where GeO₂ and Al₂O₃ are the molar concentrations of germanium and aluminum oxide in the melt.