TY - JOUR

T1 - Crystallization of Amorphous Germanium Films and Multilayer a-Ge/a-Si Structures upon Exposure to Nanosecond Laser Radiation

AU - Volodin, V. A.

AU - Krivyakin, G. K.

AU - Ivlev, G. D.

AU - Prokopyev, S. L.

AU - Gusakova, S. V.

AU - Popov, A. A.

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Abstract: The processes of the crystallization of amorphous germanium films and multilayer germanium/silicon structures upon exposure to nanosecond (70 ns) ruby laser radiation (λ = 694 nm) are studied. The samples are grown on silicon and glassy substrates by plasma-enhanced chemical vapor deposition. Pulsed laser annealing of the samples is conducted in the range of pulse energy densities E p from 0.07 to 0.8 J cm –2 . The structure of the films after annealing is determined by analyzing the scanning electron microscopy data and Raman spectra. It is established that, after annealing, the films are completely crystallized and, in this case, contain regions of coarse crystalline grains (>100 nm), whose fraction increases, as E p is increased, and reaches 40% of the area. From analysis of the position of the Raman peaks, it is conceived that the crystalline grains, whose dimensions exceed 100 nm, either contain structural defects or stretching strains. The correlation length of optical vibrations is determined from the phonon confinement model and found to increase from 5 to 8 nm, as E p is increased. Pulsed laser annealing of multilayer Ge(10 nm)/Si(5 nm) structures induces partial intermixing of the layers with the formation of Ge–Si alloys.

AB - Abstract: The processes of the crystallization of amorphous germanium films and multilayer germanium/silicon structures upon exposure to nanosecond (70 ns) ruby laser radiation (λ = 694 nm) are studied. The samples are grown on silicon and glassy substrates by plasma-enhanced chemical vapor deposition. Pulsed laser annealing of the samples is conducted in the range of pulse energy densities E p from 0.07 to 0.8 J cm –2 . The structure of the films after annealing is determined by analyzing the scanning electron microscopy data and Raman spectra. It is established that, after annealing, the films are completely crystallized and, in this case, contain regions of coarse crystalline grains (>100 nm), whose fraction increases, as E p is increased, and reaches 40% of the area. From analysis of the position of the Raman peaks, it is conceived that the crystalline grains, whose dimensions exceed 100 nm, either contain structural defects or stretching strains. The correlation length of optical vibrations is determined from the phonon confinement model and found to increase from 5 to 8 nm, as E p is increased. Pulsed laser annealing of multilayer Ge(10 nm)/Si(5 nm) structures induces partial intermixing of the layers with the formation of Ge–Si alloys.

KW - RAMAN-SPECTROSCOPY DATA

KW - SILICON FILMS

KW - HYDROGENATED SILICON

KW - EXCIMER-LASER

KW - NANOCRYSTALS

KW - GLASS

KW - PHOTOLUMINESCENCE

KW - NANOCLUSTERS

KW - PHASE

UR - http://www.scopus.com/inward/record.url?scp=85064894578&partnerID=8YFLogxK

U2 - 10.1134/S1063782619030217

DO - 10.1134/S1063782619030217

M3 - Article

AN - SCOPUS:85064894578

VL - 53

SP - 400

EP - 405

JO - Semiconductors

JF - Semiconductors

SN - 1063-7826

IS - 3

ER -