Effect of La and Y on crystallization temperatures of hafnia and zirconia

Crystallization of amorphous Y- and La-doped HfO2 and ZrO2 nanophase powders was studied using thermal analysis and high-temperature x-ray diffraction. Substantial increase of crystallization temperature of amorphous hafnium and zirconium oxides could be achieved by alloying with La2O3. The crystallization temperature of Hf2La2O7 composition is higher than 900 degreesC, which makes it a candidate for advanced gate dielectrics. In contrast, Y-doping did not significantly raise the crystallization temperature.