Atomic-layer deposition of Lu2O3

Abstract

Rare earth oxides could represent a valuable alternative to ${\mathrm{SiO}}_2$ in complementary metal–oxide–semiconductor devices. ${\mathrm{Lu}}_2{\mathrm{O}}_3$ is proposed because of its predicted thermodynamical stability on silicon and large conduction band offset. We report on the growth by atomic-layer deposition of lutetium oxide films using the dimeric ${\left\{{\left[{\mathrm{C}}_5{\mathrm{H}}_4{(\mathrm{SiMe}}_3)\right]}_2\mathrm{LuCl}\right\}}_2$ complex, which has been synthesized for this purpose, and ${\mathrm{H}}_2\mathrm{O}$ . The films were found to be stoichiometric, with ${\mathrm{Lu}}_2{\mathrm{O}}_3$ composition, and amorphous. Annealing in nitrogen at $950°\mathrm{C}$ leads to crystallization in the cubic bixbyite structure. The dielectric constant of the as-grown ${\mathrm{Lu}}_2{\mathrm{O}}_3$ layers is $12\pm 1$ .