Growth of Aluminum Molybdenum Oxide Films by Atomic Layer Deposition with Using Trimethylaluminum, Molybdenum Oxytetrachloride, and Water

In this paper, we report on the growth of aluminum molybdenum oxide (AlxMoyOz) films via atomic layer deposition (ALD) with the use of trimethylaluminum (TMA) (Al(CH3)3), molybdenum oxytetrachloride (MoOCl4), and water. The film growth process was studied in situ using a quartz crystal microbalance and ex situ using various X-ray techniques. AlxMoyOz ALD was performed using supercycles consisting of TMA/H2O and MoOCl4/H2O subcycles. We obtained two types of films, with the subcycles in the ratio 1 : 1 (1Al1MoO) and 1 : 7 (1Al7MoO). Film growth at 150°C was shown to be a linear process, with growth rate of 3.0 and 5.7 Å/supercycle for 1Al1MoO and 1Al7MoO, respectively. The density of the 1Al1MoO and 1Al7MoO films were 3.7 and 3.9 g/cm3, respectively, and their surface roughness did not exceed 20 Å. The oxidation state of the molybdenum in the films found to be 6+, 5+, and 4+. X-ray diffraction characterization showed that the films had an amorphous structure.