Liquid Injection Atomic Layer Deposition of Metallic Ru Thin Films from Ru(tmhd)3 and of High-k TiO2 Thin Films from Ti(O-i-Pr)2(tmhd)2

Abstract

Unique features of liquid delivery atomic layer deposition (LIALD) are considered in this paper in comparison to standard bubbler-type thermal ALD processes. The first part deals with the LIALD growth of metallic Ru thin films using tris(2,2,6,6-tetra-methyl-3,heptanedionato)ruthenium(III) dissolved in ethylcyclo hexane (ECH) and oxygen as metal and oxidation sources. We will show that LIALD is effective in reducing the contents of the corresponding oxides in the noble metal films. The second case deals with LIALD of TiO2 thin films with a smooth morphology from Ti(O-i-Pr)2(thd)2 dissolved in ECH as a Ti source and H2O as an oxidant. The self-saturation growth behavior of the TiO2 films was confirmed up to 390 oC. The differences in the surface roughness of the nanocrystalline LIALD TiO2 thin films obtained from Ti(O-i-Pr)2(thd)2 compared to nanocrystalline ALD TiO2 thin films from Ti(O-i-Pr)4 are discussed with respect to the differences in the nucleation behavior.