Crystallization of sputtered-deposited and ion implanted amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} thin films

Journal Article · Mon Jun 15 00:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3148288· OSTI ID:21352248

Rimini, E ^[1]; De Bastiani, R; Carria, E; Grimaldi, M G ^[2]; Nicotra, G; Bongiorno, C; Spinella, C ^[3]

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1. Dipartimento di Fisica ed Astronomia, Universita di Catania and CNR-IMM, 64 via S. Sofia, I-95123 Catania (Italy)
2. Dipartimento di Fisica ed Astronomia, Universita di Catania and MATIS CNR-INFM, 64 via S. Sofia, I-95123 Catania (Italy)
3. CNR-IMM, Stradale Primosole, 50, 95121 Catania (Italy)

X-ray diffraction and transmission electron microscopy have been utilized to measure the ion irradiation-induced modification in amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} thin films. The isothermal crystallization of sputtered-deposited and Sb{sup +} ion irradiated amorphous samples has been studied, focusing on the evolution of the microstructure during the initial stage of the transformation. In both samples, the amorphous to crystal transition occurs through the nucleation of face centered cubic (fcc) crystal domains at the film surface. A fast bidimensional growth of the crystalline nuclei in the sputtered-deposited films occurs by the generation of transrotational grains. The lattice parameter decreases as the crystalline fraction increases above 80%, and it approaches the fcc bulk value at the end of the transformation. Ion irradiation produces a densification of the deposited amorphous film (approx4% vertical shrinkage measured by atomic force microscopy) and an enhancement of the crystallization rate. Even in the irradiated amorphous, the nucleation occurs at the film surface and proceeds by the growth of the grains through the thickness of the layer although the density of the transrotational grains is strongly reduced with respect to the unirradiated amorphous. A link between the ion beam induced densification and the reduction of transrotational grains is proposed.

• OSTI ID: 21352248
• Journal Information: Journal of Applied Physics, Vol. 105, Issue 12; Other Information: DOI: 10.1063/1.3148288; (c) 2009 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIMONY COMPOUNDS
ATOMIC FORCE MICROSCOPY
CRYSTAL GROWTH
CRYSTALLIZATION
CRYSTALS
FCC LATTICES
GERMANIUM COMPOUNDS
ION BEAMS
ION IMPLANTATION
LATTICE PARAMETERS
MICROSTRUCTURE
NUCLEATION
SEMICONDUCTOR MATERIALS
SHRINKAGE
SPUTTERING
SURFACE COATING
TELLURIUM COMPOUNDS
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
BEAMS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DEPOSITION
DIFFRACTION
ELECTRON MICROSCOPY
FILMS
MATERIALS
MICROSCOPY
PHASE TRANSFORMATIONS
SCATTERING