Carbon redistribution and precipitation in high temperature ion-implanted strained Si/SiGe/Si multi-layered structures

• Published in: Microelectronic engineering 2014-08, Vol.125, p.8-13
• Main Authors: Gaiduk, P.I., Lundsgaard Hansen, J., Larsen, A. Nylandsted, Korolik, O.V., Bregolin, F.L., Skorupa, W.
• Format: Article
• Language: English
• Subjects: Carbon; Carbon redistribution; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Defects; Dopants; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Precipitates; Precipitation; Secondary ion mass spectrometry; Segregations; Separation; Silicon; Silicon germanides; Si–SiGe heterostructures; Transmission electron microscopy; Voids
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2014.01.001

Carbon depth profiles after high temperature implantation in strained Si/SiGe/Si multilayered system and induced structural defects. •Anomalous carbon segregation in strained Si/SiGe/Si structures is demonstrated.•Ion implanted C atoms are collected at the Si side and depleted at the SiGe side of the structure.•Plate-like defects and thin carbon flakes are formed along Si/SiGe interfaces.•Raman spectra include peaks at 1600 and 2700cm−1, associated with carbon-related phase.•The concept of strain-enhanced separation of point defects and dopant precipitation is discussed. We report on the segregation of carbon atoms and structural transformations in strained multilayered Si/SiGe/Si structures after molecular-beam epitaxial (MBE) growth, carbon ion implantation and thermal treatment at different conditions. The idea behind this study was that due to their specific strain distribution, pseudomorphic layers of Si/SiGe promote spatial separation of vacancies and interstitials followed by segregation of foreign dopant atoms. High temperature ion implantation was used for injection of carbon atoms as well as point defects in the strained layers. The defects were investigated by transmission electron microscopy (TEM), dopant depth profiles by secondary-ion-mass spectrometry (SIMS), and optical properties by Raman scattering measurements. Based on SIMS data we demonstrate anomalous redistribution of the implanted carbon atoms around the strained SiGe/Si layers which results in their accumulation on the Si side and depletion on the SiGe side of the structure. The TEM study demonstrates formation of plate-like defects, stacking faults and thin carbon-precipitated flakes distributed along the Si/SiGe interfaces. Raman spectra reveal peaks at 1600 and 2700cm−1 which might be associated with carbon-related phases. The concept of strain-enhanced separation of point defects and dopant precipitation is discussed.