Impact of precursor chemistry on atomic layer deposition of lutetium aluminates

Abstract

Physical and electrical characterizations of ultrathin Si-rich Hf-silicate film and Hf-silicate/ Si O 2 bilayer deposited by atomic layer chemical vapor deposition Rare earth-based oxides are of interest for their potential application in future logic highperformance technologies where Germanium is the channel material. In addition, their aluminates are considered as promising high-k dielectrics for nonvolatile memory technologies. However, it has been found that the dielectric quality of these materials is highly dependent on the method of preparation. The authors have therefore examined the atomic layer deposition (ALD) of Lu x Al 2Àx O 3 layers by means of Tris(isopropyl cyclopentadienyl) Lutetium (Lu( i PrCp) 3 ), Tris(diethyl-amido)aluminum and H 2 O or O 3 in a nanolaminate approach. This manuscript covers the impact of the oxidizer on both the ALD process characteristics and Lu x Al 2Àx O 3 layer properties. Because of the hygroscopic nature of rare earth oxides, the O 3 -based ALD of Lu x Al 2Àx O 3 is well controlled compared to the H 2 O-based process. On the other hand, Lu x Al 2Àx O 3 dielectrics grown with H 2 O as the oxidizer show better electrical properties in terms of Equivalent Oxide Thickness (EOT) and leakage current density because of lower C impurities, especially in case of Lu-rich compositions.

Atomic layer deposition of scandium‐based oxides

“…This trend results from the increasing contribution of gas phase depositions between the sorbed H 2 O and the Gd( i PrCp) 3 precursor. Comparable behavior has been observed during the ALD of Lu x Al 2− x O 3 , as Lu 2 O 3 is also known to be hygroscopic. In contrast, no influence is observed when more Sc(MeCp) 3 /H 2 O subcycles are applied.…”