Regensburg 2025 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 13: Poster
DS 13.56: Poster
Donnerstag, 20. März 2025, 18:00–20:00, P1
Mechanical stress of Ge films upon ion irradiation — •Karla Paz Corrales1, Aaron Reupert2, Berit Marx-Glowna3, Martin Hafermann1, Elke Wendler1, and Carsten Ronning1 — 1Institute of Solid State Physics, Friedrich Schiller University Jena, Helmholtzweg 3, 07743 Jena, Germany — 2Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Lessingstraße 12-14, D-07743 Jena, Germany — 3Helmholtz Institute Jena, Fröbelstieg 3, D-07743 Jena, Germany
Mechanical stress in thin films significantly affects the performance, reliability, and durability of optoelectronic components. Polycrystalline films are considered to be in a "stressed state" due the mismatch of the thermal expansion coefficients between the film and substrate. Amorphous Ge films (~600nm) were deposited on fused silica substrates by magnetron sputtering. Subsequent annealing was performed at 600°C for 1h and 7h in vacuum to achieve crystallization. GIXRD patterns show peaks related to the polycrystalline Ge with preferred orientation along the [111] direction. Laser curvature measurements showed compressive stress for amorphous Ge-films, while the polycrystalline Ge samples became tensile stressed after annealing. In situ curvature measurements during ion-irradiation, using Au ions with 1.8 MeV on the polycrystalline Ge, show a decrease in stress with increasing irradiation fluence. Furthermore, optical measurements were performed after irradiation, and a reduction in the reflectance region of 450 to 650 nm and a shift of the absorption region up to ~1000 nm were observed due to ion beam-induced defect formation.
Keywords: irradiation; mechanical stress; polycrystalline germanium