Epitaxial metastable Ge{sub 1-y}C{sub y} (y{<=}0.02) alloys grown on Ge(001) from hyperthermal beams: C incorporation and lattice sites

Journal Article · Sat Jul 01 04:00:00 EDT 2000 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.373629· OSTI ID:20216836

D'Arcy-Gall, J ^[1]; Desjardins, P ^[1]; Petrov, I ^[1]; Greene, J E ^[1]; Paultre, J -E ^[2]; Masut, R A ^[2]; Gujrathi, S C ^[3]; Roorda, S ^[3]

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1. Materials Science Department, the Coordinated Science Laboratory, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin Avenue, Urbana, Illinois 61801 (United States)
2. Groupe de Recherche en Physique et Technologie des Couches Minces and Departement de Genie Physique et de Genie des Materiaux, Ecole Polytechnique de Montreal, P.O. Box 6079, Station Centre-Ville, Montreal, Quebec H3C 3A7, (Canada)
3. Groupe de Recherche en Physique et Technologie des Couches Minces and Departement de Physique, Universite de Montreal, P.O. Box 6128, Station Centre-Ville, Montreal, Quebec H3C 3J7, (Canada)

Epitaxial metastable Ge{sub 1-y}C{sub y} alloy layers with y{<=}0.02 were grown on Ge(001) at temperatures T{sub s}=200-550 degree sign C using hyperthermal Ge and C beams with average energies of 16 and 24 eV, respectively, in order to investigate C incorporation pathways in the Ge lattice. High-resolution reciprocal lattice maps show that all as-deposited alloy layers are fully coherent with the substrate. Layers grown at T{sub s}{<=}350 degree sign C are in compression due to higher C concentrations in interstitial than in substitutional sites. The compressive strain decreases (i.e., the substitutional C concentration increases) with increasing T{sub s} within this temperature range. At higher growth temperatures, as-deposited alloys are nearly strain free since the majority of the incorporated C is trapped at extended defects. Annealing the Ge{sub 1-y}C{sub y} layers at T{sub a}=450 and 550 degree sign C leads to a significant increase, proportional to the strain in the as-deposited films, in compressive strain. Further annealing at T{sub a}=650 degree sign C results in the formation of dislocation loops which act as sinks for interstitial and substitutional C atoms and thus relieves residual macroscopic strain. Finally, we show that the large compressive strain associated with interstitial C atoms must be accounted for in order to determine the total incorporated C fraction from diffraction analyses. (c) 2000 American Institute of Physics.

• OSTI ID: 20216836
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 1 Vol. 88; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CARBIDES
ENERGY BEAM DEPOSITION
EPITAXY
EXPERIMENTAL DATA
GERMANIUM ALLOYS
INTERSTITIALS
METASTABLE STATES
STRAINS
THIN FILMS
X-RAY DIFFRACTION