Atomic layer deposition of dielectric Y2O3 thin films from a homoleptic yttrium formamidinate precursor and water

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Nils Boysen - , Ruhr University Bochum (Author)
  • David Zanders - , Ruhr University Bochum (Author)
  • Thomas Berning - , Ruhr University Bochum (Author)
  • Sebastian M.J. Beer - , Ruhr University Bochum (Author)
  • Detlef Rogalla - , Ruhr University Bochum (Author)
  • Claudia Bock - , Ruhr University Bochum (Author)
  • Anjana Devi - , Ruhr University Bochum (Author)

Abstract

We report the application of tris(N,N′-diisopropyl-formamidinato)yttrium(iii) [Y(DPfAMD)3] as a promising precursor in a water-assisted thermal atomic layer deposition (ALD) process for the fabrication of high quality Y2O3 thin films in a wide temperature range of 150 °C to 325 °C. This precursor exhibits distinct advantages such as improved chemical and thermal stability over the existing Y2O3 ALD precursors including the homoleptic and closely related yttrium tris-amidinate [Y(DPAMD)3] and tris-guanidinate [Y(DPDMG)3], leading to excellent thin film characteristics. Smooth, homogeneous, and polycrystalline (fcc) Y2O3 thin films were deposited at 300 °C with a growth rate of 1.36 Å per cycle. At this temperature, contamination levels of C and N were under the detectable limits of nuclear reaction analysis (NRA), while X-ray photoelectron spectroscopy (XPS) measurements confirmed the high purity and stoichiometry of the thin films. From the electrical characterization of metal-insulator-semiconductor (MIS) devices, a permittivity of 13.9 at 1 MHz could be obtained, while the electric breakdown field is in the range of 4.2 and 6.1 MV cm-1. Furthermore, an interface trap density of 1.25 × 1011 cm-2 and low leakage current density around 10-7 A cm-2 at 2 MV cm-1 are determined, which satisfies the requirements of gate oxides for complementary metal-oxide-semiconductor (CMOS) based applications.

Details

Original languageEnglish
Pages (from-to)2565-2574
Number of pages10
JournalRSC advances
Volume11
Issue number5
Publication statusPublished - 12 Jan 2021
Peer-reviewedYes
Externally publishedYes

Keywords