Si exfoliation by MeV proton implantation

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2012-04, Vol.277, p.93-97
• Main Authors: Braley, Carole, Mazen, Frédéric, Tauzin, Aurélie, Rieutord, François, Deguet, Chrystel, Ntsoenzok, Esidor
• Format: Article
• Language: English
• Subjects: Annealing; Blistering; Crystal defects; Delamination; Evolution; Fluence; Implantation; Orientation; Separation; Silicon; Silicon substrates; Smart Cut
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2011.12.056

Proton implantation in silicon and subsequent annealing are widely used in the Smart Cut™ technology to transfer thin layers from a substrate to another. The low implantation energy range involved in this process is usually from a few ten to a few hundred of keV, which enables the separation of up to 2μm thick layers. New applications in the fields of 3D integration and photovoltaic wafer manufacturing raise the demand for extending this technology to higher energy in order to separate thicker layer from a substrate. In this work, we propose to investigate the effect of proton implantation in single crystalline silicon in the 1–3MeV range which corresponds to a 15–100μm range for the hydrogen maximum concentration depth. We show that despites a considerably lower hydrogen concentration at Rp, the layer separation is obtained with fluence close to the minimum fluence required for low energy implantation. It appears that the fracture propagation in Si and the resulting surface morphology is affected by the substrate orientation. Defects evolution is investigated with Fourier Transform Infrared Spectroscopy. The two orientations reveal similar type of defects but their evolution under annealing appears to be different.