Thermal atomic layer deposition of ErO films from a volatile, thermally stable enaminolate precursor.

Thin films of ErO films were grown by atomic layer deposition using the Er precursor tris(1-(dimethylamino)-3,3-dimethylbut-1-en-2-olate)erbium(III) (Er(L)), with water as the co-reactant. Saturative, self-limited growth was observed at a substrate temperature of 200 °C for pulse lengths of ≥4.0 s for Er(L) and ≥0.2 s for water. An ALD window was observed from 175 to 225 °C with a growth rate of about 0.25 Å per cycle. ErO films grown at 200 °C on Si(100) and SiO substrates with a thickness of 33 nm had root mean square surface roughnesses of 1.75 and 0.75 nm, respectively. Grazing incidence X-ray diffraction patterns showed that the films were composed of polycrystalline ErO at all deposition temperatures on Si(100) and SiO substrates. X-ray photoelectron spectroscopy revealed stoichiometric ErO, with carbon and nitrogen levels below the detection limits after argon ion sputtering to remove surface impurities. Transmission electron microscopy studies of ErO film growth in nanoscale trenches (aspect ratio = 10) demonstrated conformal coverage.