Observation of the interface of Ba/Si(100) by MDS and TDS

• Published in: Applied surface science 1994-12, Vol.82 (1-4), p.537-542
• Main Authors: Hongo, Shozo, Ojima, Kaoru, Taniguchi, Shinichi, Urano, Toshio, Kanaji, Toru
• Format: Article
• Language: English
• Subjects: Composition; defects and impurities; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Surface double layers, schottky barriers, and work functions; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/0169-4332(94)90271-2

The interaction of Ba overlayers with Si(100)2 x 1 surfaces and barium silicide formation are studied for Ba coverages up to θ = 10 ML by MDS (metastable deexcitation spectroscopy) and TDS (thermal desorption spectroscopy). TDS spectra of Ba from Ba/Si(100) are observed as a function of Ba coverage. The process of Ba dosing on Si(100)2 x 1 and the annealing process are observed by MDS as a function of Ba coverage and as a function of sample annealing temperature, respectively. The work function change is measured as a function of the annealing temperature simultaneously. It is found from the above experiments that no silicide formation takes place by heating up to 800°C in the system of submonolayer Ba on Si(100)2 x 1 and that silicide is formed very easily by heating up to 250°C in the system of 2 ML Ba/Si(100)2 x 1. The Si—Ba bond is so tight that the Ba atoms bonded to the substrate Si atoms cannot move easily to form three-dimensional barium silicide. Therefore more than a few Ba layers are necessary to form barium silicide on the Si(100) surface.