Formation of GdSi2 film on Si(111) via phase transformation assisted by interfacial SiO2 layer

Abstract

Phase selective synthesis of gadolinium silicide films on Si(111) using an interfacial SiO2 layer GdSi 2 film with almost perfect interface was grown on a Si͑111͒ substrate via phase transformation assisted by interfacial SiO 2 layer. The evolution of Gd silicide and the role of an oxide layer were investigated by using in situ reflection of high-energy electron diffraction, x-ray diffraction (XRD), atomic force microscopy (AFM), x-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The XRD and AFM results confirm structural transformation from the initial GdSi 1.7 layer to the GdSi 2 layer after the post-annealing at 900°C. The HRTEM image suggests that the formation of GdSi 2 follows kinetic growth process, where the grain growth is dominated by the abundance of Si at the reacting surface. The thermally decomposed interfacial oxide initiates rapid phase transformation and finally results in almost perfect GdSi 2 / Si interface without any residual oxide or mixed structure.

Interaction of Oxygen and Gadolinium with Si(100)-2x1 Surface. Formation of a System with 1-eV Work Function

“…1), which is determined by a lower intensity of the Auger line with an energy of 68 eV. The VB-PES of this stable system reveals an intense spectral peculiarity with a maximum in the energy interval (𝐸 F −5.5 eV, 𝐸 F −5.3 eV), which, in accordance with the literature data [9,10,19], can be attributed to the states of oxygen 2𝑝 electrons, and a much less intense spectral peculiarity at 𝐸 F − 3.2 eV.…”

“…Of interest is the Gd ability to form nanowires with unique properties on the Si surface [2][3][4][5], as well as the fact that gadolinium hexaboride has a low value of work function (𝜙 ≈ 1.5 eV) and is considered as a material for emission electronics [5,6]. In connection with all that, the interaction of rare-earth elements, in particular, Gd, is studied rather intensively by various research groups [7][8][9][10][11][12][13][14][15][16][17][18][19]. In the cited works, it was found that Gd promotes the oxidation of the Si surface.…”