Research output: Contribution to journal › Article › peer-review
Single-shot selective femtosecond and picosecond infrared laser crystallization of an amorphous Ge/Si multilayer stack. / Volodin, V. A.; Cheng, Yuzhu; Bulgakov, A. V. et al.
In: Optics and Laser Technology, Vol. 161, 109161, 06.2023, p. 10.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Single-shot selective femtosecond and picosecond infrared laser crystallization of an amorphous Ge/Si multilayer stack
AU - Volodin, V. A.
AU - Cheng, Yuzhu
AU - Bulgakov, A. V.
AU - Levy, Y.
AU - Beránek, J.
AU - Nagisetty, S. S.
AU - Zukerstein, M.
AU - Popov, A. A.
AU - Bulgakova, N. M.
N1 - We are grateful to G.K. Krivyakin for the HRTEM measurements and to the Center for Collective Use “VTAN” NSU for providing equipment for Raman spectroscopy and HRTEM image analysis. The study of V.A.V. and Y.C. was supported by the Ministry of Science and Higher Education of the Russian Federation, project No. 075-15-2020-797 (13.1902.21.0024). A.V.B., Y.L., J.B., M.Z., and N.M.B. acknowledge support of the European Regional Development Fund and the state budget of the Czech Republic (project BIATRI: No. CZ.02.1.01/0.0/0.0/15_003/0000445). J.B. acknowledges also support of the Grant Agency of the Czech Technical University in Prague, grant No. SGS22/188/OHK4/3T/14.
PY - 2023/6
Y1 - 2023/6
N2 - Pulsed laser crystallization is an efficient annealing technique to obtain polycrystalline silicon or germanium films on non-refractory substrates. This is important for creating “flexible electronics” and can also be used to fabricate thin-film solar cells. In this work, near- and mid-infrared femtosecond and picosecond laser pulses were used to crystallize a Ge/Si multilayer stack consisting of alternating amorphous thin films of silicon and germanium. The use of infrared radiation at wavelengths of 1030 and 1500 nm with photon energies lower than the optical absorption edge in amorphous silicon allowed obtaining selective crystallization of germanium layers with a single laser shot. The phase composition of the irradiated stack was investigated by the Raman scattering technique. Several non-ablative regimes of ultrashort-pulse laser crystallization were found, from partial crystallization of germanium without intermixing the Ge/Si layers to complete intermixing of the layers with formation of GexSi1-x solid alloys. The roles of single- and two-photon absorption, thermal and non-thermal (ultrafast) melting processes, and laser-induced stresses in selective pico- and femtosecond laser annealing are discussed. It is concluded that, due to a mismatch of the thermal expansion coefficients between the adjacent stack layers, efficient explosive solid-phase crystallization of the Ge layers is possible at relatively low temperatures, well below the melting point.
AB - Pulsed laser crystallization is an efficient annealing technique to obtain polycrystalline silicon or germanium films on non-refractory substrates. This is important for creating “flexible electronics” and can also be used to fabricate thin-film solar cells. In this work, near- and mid-infrared femtosecond and picosecond laser pulses were used to crystallize a Ge/Si multilayer stack consisting of alternating amorphous thin films of silicon and germanium. The use of infrared radiation at wavelengths of 1030 and 1500 nm with photon energies lower than the optical absorption edge in amorphous silicon allowed obtaining selective crystallization of germanium layers with a single laser shot. The phase composition of the irradiated stack was investigated by the Raman scattering technique. Several non-ablative regimes of ultrashort-pulse laser crystallization were found, from partial crystallization of germanium without intermixing the Ge/Si layers to complete intermixing of the layers with formation of GexSi1-x solid alloys. The roles of single- and two-photon absorption, thermal and non-thermal (ultrafast) melting processes, and laser-induced stresses in selective pico- and femtosecond laser annealing are discussed. It is concluded that, due to a mismatch of the thermal expansion coefficients between the adjacent stack layers, efficient explosive solid-phase crystallization of the Ge layers is possible at relatively low temperatures, well below the melting point.
KW - Explosive low-temperature crystallization
KW - Germanium/silicon multilayer stack
KW - Nonlinear light absorption
KW - Raman spectroscopy
KW - Selective crystallization
KW - Ultrashort infrared laser crystallization
UR - https://www.scopus.com/inward/record.url?eid=2-s2.0-85146431519&partnerID=40&md5=9c6097dc1d2f63526e7571839ff7eb51
UR - https://www.mendeley.com/catalogue/ca879444-0e23-30fe-8c17-77480260839d/
U2 - 10.1016/j.optlastec.2023.109161
DO - 10.1016/j.optlastec.2023.109161
M3 - Article
VL - 161
SP - 10
JO - Optics and Laser Technology
JF - Optics and Laser Technology
SN - 0030-3992
M1 - 109161
ER -
ID: 49082613