Formation of strontium template on Si(1 0 0) by atomic layer deposition

• Published in: Applied surface science Vol. 257; no. 11; pp. 4826 - 4830
• Main Authors: Zhang, C.B., Wielunski, L., Willis, B.G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.03.2011; Elsevier
• Subjects: Atomic layer deposition; Auger electron spectroscopy; Catalyzed deoxidation process; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Epitaxial growth; Exact sciences and technology; High- k oxides; Molecular beam epitaxy; Oxides; Physics; Semiconductors; Short range order; Silicon; Silicon substrates; Strontium; Strontium; Silicon; Atomic layer deposition; High- k oxides; Catalyzed deoxidation process; High-k oxides
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2010.12.098

▶ Epitaxial template layers for crystalline oxide heteroepitaxy on silicon have been grown by ALD. ▶ Ordered reconstructions of Sr/Si monolayers have been achieved by ALD with oxide desorption. ▶ Carbonate free SrO growth was achieved by ALD with cyclopentadienyl Sr precursor and water reactants. ▶ Silicate layers are proposed as intermediates for the formation of the epitaxial Sr layers. ▶ The present results demonstrate that ALD is a potential alternative to molecular beam epitaxy methods for the fabrication of epitaxial oxides on semiconductor substrates. The formation of ordered Sr overlayers on Si(1 0 0) by Atomic Layer Deposition (ALD) from bis(triisopropylcyclopentadienyl) Strontium (Sr(C 5 i Pr 3H 2) 2) and H 2O has been investigated. SrO overlayers were deposited on a 1–2 nm SiO 2/Si(1 0 0) substrate, followed by a deoxidation process to remove the SiO 2 layer at high temperatures. Auger electron spectroscopy, Rutherford backscattering spectrometry, spectroscopic ellipsometry, and low-energy electron diffraction were used to investigate the progress of both ALD and deoxidation processes. Results show that an ordered Sr/Si(1 0 0) surface with 2 × 1 pattern can be obtained after depositing several monolayers of SrO on Si using ALD followed by an anneal at 800–850 °C. The (2 × 1) ordered Sr/Si(1 0 0) surface is known to be an excellent template for the epitaxial growth of SrTiO 3 (STO) oxide. The present results demonstrate that ALD is a potential alternative to molecular beam epitaxy methods for the fabrication of epitaxial oxides on semiconductor substrates.