Growth, Structure, and Thermal Conductivity of Yttria-Stabilized Hafnia Thin Films (Postprint).

摘要

Yttria-stabilized hafnia (YSH) films of 90 nm thickness have been produced using sputter-deposition by varying the growth temperature (Ts) from room-temperature (RT) to 400 deg C. The effect of Ts on the structure, morphology, and thermal conductivity of YSH films has been investigated. Structural studies indicate that YSH films crystallize in the cubic phase. The lattice constant decreases from 5.15 to 5.10 A with increasing Ts. The average grain size (L) increases with increasing Ts;L-Ts relationship indicates the thermally activated process of the crystallization of YSH films. The analyses indicate a critical temperature to promote nanocrystalline, cubic YSH films in 300 deg C, which is higher comparte to that of pure monoclinic HfO2 films. Compared to pure nanocrystalline hafnia, the addition of yttria lowers the effective thermal conductivity. The effect of grain size on thermal conductivity is also explored.