Formation of epitaxial erbium–silicide islands on Si(0 0 1)

• Published in: Surface science Vol. 578; no. 1; pp. 142 - 148
• Main Authors: Pető, G., Molnár, G., Horváth, Z.E., Daróczi, Cs.S., Zsoldos, É., Gyulai, J.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 10-03-2005; Amsterdam Elsevier Science; New York, NY
• Subjects: AFM; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Epitaxy; Erbium; Exact sciences and technology; Physics; RHEED; Self-assembly; Silicides; AFM; Self-assembly; RHEED; Silicides; Epitaxy; Erbium; Atomic force microscopy; Rare earths; Silicon; Island structure; Surface structure
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2005.01.027

Erbium films of 0.5, 2 and 6
nm thickness were evaporated in UHV onto Si(0
0
1) substrates, annealed and characterized in situ by reflected high-energy-electron diffraction (RHEED). The RHEED pattern was streaky for ErSi
2−
x
films at all thicknesses were formed at 400
°C. A heat treatment of the 0.5 and 2
nm thick Er films at 800
°C induced an inhomogeneous surface showing RHEED patterns both of the Si(0
0
1) substrate and the epitaxial ErSi
2−
x
. The same effect was observed after successive repetition of Er depositions, 12 times for the 0.5
nm and three times for the 2
nm thick Er films. In contrast for a 6
nm Er layer the RHEED pattern remained unchanged after the heat treatment at 800
°C. Atomic force microscopy (AFM) indicated the formation of a quasi-continuous layer with roughness independent of the Er film thickness. Cross-sectional transmission electron microscopy (XTEM) showed structures with a “hut like” form. This “continuous–discontinuous” like transformation of the epitaxial ErSi
2−
x
film cannot be explained by only the well known strain effect.