Correlation between structure and properties of Er2O3 nanocrystalline thin films

Er2O3 thin films have been deposited by low-pressure metalorganic chemical vapor deposition (MOCVD) also plasma assisted (RP-MOCVD), using tris(isopropylcyclopentadienyl)erbium and O2 on Si(1 0 0), Si(1 1 1) and corning glass substrates. The RP-MOCVD approach produced highly (1 0 0)-oriented, dense and mechanically stable Er2O3 films with columnar structure, while films with (1 1 1) texture are deposited by MOCVD. A high refractive index of 2.1 at 589.3 nm comparable to that of bulk single crystalline Er2O3, a high transparency in the vis-near UV range and an optical band-gap of 6.5 eV have been found, which make Er2O3 interesting as antireflective and protective coating. A static dielectric constant k ∼ 12, a density of interface traps as low as 4.2 × 1010 cm2 eV−1, for 5–10 nm thick Er2O3 layers grown on Si(1 0 0), render the present Er2O3 films interesting also as high-k dielectric in CMOS devices.