Photoelectron spectroscopy study of GeSn epitaxial layers for photonic applications

• Published in: Microelectronic engineering Vol. 253; p. 111663
• Main Authors: Bouschet, M., Martinez, E., Fabbri, J.M., Casiez, L., Quintero, A., Da Fonseca, J., Jany, C., Rodriguez, P., Chelnokov, A., Hartmann, J.M., Reboud, V., Renault, O.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2022; Elsevier BV; Elsevier
• Subjects: Ammonium sulfides; Band gap; Band structure; Band structure of solids; Emission analysis; Engineering Sciences; Epitaxial layers; Germanium; Intermetallic compounds; Materials; Micro and nanotechnologies; Microelectronics; Oxidation; Photoelectrons; Scanning electron microscopy; Spectrum analysis; Surface treatment; X ray photoelectron spectroscopy
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2021.111663

We have investigated with X-ray Photoelectron Spectroscopy (XPS) the impact of different wet cleanings on the surface of thick GeSn 13% direct band-gap layers grown on germanium strain relaxed buffers. The XPS time-dependent study showed a fast Ge re-oxidation after only a few minutes, while tin was more stable. A dip in (NH4)2S after the 5 min surface treatment with HCl/HF (1% / 10%) slowed germanium re-oxidation. Optimized surface cleanings enabled us to investigate GeSn band structure by momentum-resolved Photo-Emission Electron Microscopy (kPEEM). The obtained band structure images of an ex-situ prepared GeSn 13% surface were discussed. [Display omitted] •Thick GeSn growth on Ge strain relaxed buffers•GeSn surface cleaning and passivation•GeSn band structure investigation by momentum-resolved Photo-Emission Electron Microscopy