Atomic Layer Deposition of Gadolinium Aluminate using Gd(iPrCp)3, TMA, and O3 or H2O

For future generations of non-volatile memory applications, the replacement of the interpoly dielectric by a suitable high-k material is required. Rare-earth aluminates are potential candidates because they are predicted to combine a high dielectric permittivity with a large band gap. We demonstrate the atomic layer deposition (ALD) of GdxAl2-xO3 layers using Gd( i PrCp)3, trimethyl-aluminum (TMA), and H2 Oo r O3. Process windows for both H2O and O3 as oxidants are explored. H2O is shown to lead to better GdxAl2-xO3 film properties than O3, although the accessible composition range is limited because of the hygroscopic nature of Gd2O3.