Atomic Layer Deposition of Hafnium and Zirconium Oxides Using Metal Amide Precursors

TLDR

Deposition reactor design and ALD cycle design for hafnium and zirconium oxide films using metal amide precursors are discussed. Atomic layer deposition of hafnium and zirconium oxides was performed using six metal alkylamide precursors and water as the oxygen source, with deposition temperatures ranging from 50 to 500 °C and precursor vaporization temperatures of 40 to 140 °C, and vapor pressures measured across a wide temperature range. The resulting films were smooth with substrate‑matched roughness, exhibited 100 % step coverage on high‑aspect‑ratio holes, uniform thickness and composition across the reactor, a 2:1 oxygen‑to‑metal ratio, no detectable impurities, and the precursors were highly reactive with hydroxylated surfaces.

Abstract

Atomic layer deposition (ALD) of smooth and highly conformal films of hafnium and zirconium oxides was studied using six metal alkylamide precursors for hafnium and zirconium. Water was used as an oxygen source during these experiments. As deposited, these films exhibited a smooth surface with a measured roughness equivalent to that of the substrate on which they were deposited. These films also exhibited a very high degree of conformality: 100% step coverage on holes with aspect ratios greater than 35. The films were completely uniform in thickness and composition over the length of the deposition reactor. The films were free of detectable impurities and had the expected (2:1) oxygen-to-metal ratio. Films were deposited at substrate temperatures from 50 to 500 °C from precursors that were vaporized at temperatures from 40 to 140 °C. The precursors were found to be highly reactive with hydroxylated surfaces. Their vapor pressures were measured over a wide temperature range. Deposition reactor design and ALD cycle design using these precursors are discussed.