Surface electron-diffraction patterns of β-FeSi2 films epitaxially grown on silicon

Abstract

Semiconducting /3-FeSi 2 is drawing much current research interest because of hoped-for silicon-based optoelectronics applications. The study of heteroepitaxial film growth on silicon depends heavily upon several transmission and reflection electron-diffraction techniques. Because of the complicated crystal structure of this material, the possibility of competing heteroepitaxial relationships, the propensity for formation of epitaxial variants by rotation twinning, and the uncertainty in the crystalline surface nets, the analysis of experimental diffraction patterns is complicated. A theoretical reference for a number of fundamental electron-diffraction patterns is provided and they are illustrated with a broad range of experimentally obtained patterns from the surfaces of epitaxial films. In situ transmission reflection high-energy electron diffraction (RHEED) (transmission electron diffraction with conventional RHEED instrumentation), from rough but epitaxial films, is of great utility and quite feasible with epitaxial systems such as this one, which exhibit a tendency toward islanding. The possibilities for experimentally distinguishing, with this technique, the competing epitaxial relationships on Si ( 111) are clarified; it is found that the /3-FeSi 2 ( 110) matching face is certainly present in these samples and the (101) may be also. An experimental determination of the two-dimensional space groups of the ( 100), (110), and (1 01) faces is also presented-in the first and third cases the surface unit meshes are different from the simple projections of the bulk crystalline unit cell.

Conduction properties of β‐FeSi2 epitaxial films with low carrier density

“…On the other hand, the number of variant differs in the epitaxial films. In the epitaxial relationship of β-FeSi 2 on Si substrates, there are two variants in the β-FeSi 2 (100)//Si(001) film, and three variants in the β-FeSi 2 (110)(101)//Si(111) films [11,12]. These variants form defect levels with different ionization energy in the bandgap.…”

Application of sputter etching treatment to the formation of semiconducting silicide film on Si substrate

“…Analysis of the pattern revealed the so-called "type A" epitaxial relationship, i.e. FeSi 2 (100) // Si (100) with FeSi 2 [010] // Si 011 [7], While RHEED monitors in-situ the surface structures during the course of film fabrication, the films were taken out of the deposition chamber for X-ray diffraction (XRD; MXP3T, MAC Science) and transmission electron microscopy (TEM; JEM-3000F, JEOL Ltd.) observation. The conditions for the formation of epitaxial -FeSi 2 films on Si (100) substrate with IBSD method was investigated [8].…”

Surface morphology and luminescence characterization of β-FeSi2 thin films prepared by pulsed laser deposition

“…After annealing, no peaks other than those from the be observed in all the samples. The orientation of b-FeSi 2 with respect to the Si (1 1 1) surface agrees with the epitaxial face relationship between the two materials[16]. The forbidden diffraction peak of Si (2 2 2) is produced by double diffraction.…”