Multifunctional Nanocrystalline Thin Films of Er2O3: Interplay between Nucleation Kinetics and Film Characteristics

✍ Scribed by M. Losurdo; M. M. Giangregorio; P. Capezzuto; G. Bruno; R. G. Toro; G. Malandrino; I. L. Fragalà; L. Armelao; D. Barreca; E. Tondello; A. A. Suvorova; D. Yang; E. A. Irene

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 290 KB
• Volume: 17
• Category: Article
• ISSN: 1616-301X
• DOI: 10.1002/adfm.200700524

✦ Synopsis

Abstract

In this study, thin films of Er~2~O~3~ are deposited by low‐pressure metal–organic chemical vapor deposition (MOCVD) using a tris(isopropylcyclopentadienyl)erbium precursor and O~2~ on various substrates, including p‐type Si(100), Si(111), Corning glass, and c‐axis‐oriented α‐Al~2~O~3~(0001). The resulting films are extensively characterized in order to demonstrate their applicability as antireflective and protective coatings and as high‐k gate dielectrics. The interplay existing among the substrate, the nucleation kinetics, and the resulting structural, morphological, optical, and electrical properties of Er~2~O~3~ thin films is explored. Fast nucleation governed by surface energy minimization characterizes the growth of (111)‐oriented Er~2~O~3~ on Si(100), glass, and α‐Al~2~O~3.~ Conversely, nonhomogeneous nucleation leads to polycrystalline Er~2~O~3~ on Si(111) substrates. Er~2~O~3~ films grown on Si(100) possess superior characteristics. A high refractive index of 2.1 at 589.3 nm, comparable to the value for bulk single crystalline Er~2~O~3~, a high transparency in the near UV‐vis range, and an optical bandgap of 6.5 eV make Er~2~O~3~ interesting as an antireflective and protective coating. A static dielectric constant of 12–13 and a density of interface traps as low as 4.2 × 10^10^ cm^2^ eV^–1^ for 5–10 nm thick Er~2~O~3~ layers grown on Si(100) render the present Er~2~O~3~ films interesting also as high‐k dielectrics in complementary metal oxide semiconductor (CMOS) devices.