Single-shot selective femtosecond and picosecond infrared laser crystallization of an amorphous Ge/Si multilayer stack

0571614 - FZÚ 2024 RIV NL eng J - Článek v odborném periodiku
Volodin, V.A. - Cheng, Y.-Z. - Bulgakov, Alexander - Levy, Yoann - Beránek, Jiří - Nagisetty, Siva S. - Zukerstein, Martin - Popov, A. A. - Bulgakova, Nadezhda M.
Single-shot selective femtosecond and picosecond infrared laser crystallization of an amorphous Ge/Si multilayer stack.
Optics and Laser Technology. Roč. 161, June (2023), č. článku 109161. ISSN 0030-3992. E-ISSN 1879-2545
Grant CEP: GA MŠMT EF15_003/0000445
Grant ostatní: OP VVV - BIATRI(XE) CZ.02.1.01/0.0/0.0/15_003/0000445
Institucionální podpora: RVO:68378271
Klíčová slova: Germanium/silicon multilayer stack * ultrashort infrared laser crystallization * selective crystallization * explosive low-temperature crystallization * Raman spectroscopy * nonlinear light absorption
Obor OECD: Optics (including laser optics and quantum optics)
Impakt faktor: 5, rok: 2022
Způsob publikování: Omezený přístup
https://doi.org/10.1016/j.optlastec.2023.109161

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 temper atures, well below the melting point.
Trvalý link: https://hdl.handle.net/11104/0349444