Epitaxial recrystallization of amorphous Si layers by swift heavy ions P.K. Sahoo a,b, * , T. Mohanty c , D. Kanjilal c , A. Pradhan a , V.N. Kulkarni a a Department of Physics, Indian Institute of Technology, Kanpur 208016, India b Instituut voor Kern- en Stralingsfysica and INPAC, KU Leuven, B-3001 Leuven, Belgium c Inter-University Accelerator Center, New Delhi 110067, India Available online 8 January 2007 Abstract Epitaxial recrystallization of 200 nm amorphous Si layers by swift heavy ions (50 and 100 MeV Au 8+ ) and the role of electronic energy loss was investigated by Rutherford backscattering spectrometry and Micro-Raman spectroscopy. We observed good epitaxial crystal- lization in the range of 473–673 K, which is a much lower temperature regime as compared to the one needed for conventional solid phase epitaxial growth. Planar recrystallization has been observed as a function of temperature giving rise to an activation energy of 0.26 ± 0.02 eV. A considerable amount of stress still remains even after full epitaxy at 673 K implantation. A possible mechanism of recrystallization is discussed on the basis of the production of vacancies along the track of the swift heavy ion and their migration at elevated temperatures. Ó 2007 Elsevier B.V. All rights reserved. PACS: 61.85.+P; 61.80.Jh Keywords: IBIEC; Swift heavy ions; RBS-channeling; Recrystallization 1. Introduction In semiconductor device technologies, doping of Si or other semiconductors by ion implantation involves an important step of recovering the damage/amorphization induced by the energetic ions in the lattice [1–6]. The well-established method for achieving original crystalline structure is furnace annealing via solid phase epitaxial growth (SPEG) [7,8]. It has been extensively investigated to remove the damage and incorporate the dopants in sub- stitutional lattice positions in the case of ion beam amor- phized crystalline silicon. As an example, in case of Si the annealing temperatures greater than 823 K are generally needed for SPEG process. With the reduction in the size of the devices to submicron scales it has become a challenge to regain the lattice structure at lower temperatures to avoid undesired diffusion of the dopants [9]. It was realized that SPEG could also be observed in silicon at ambient temperatures as low as 473–673 K by simultaneous irradi- ation with energetic ions [9–14]. These studies have ade- quately demonstrated that the recrystallization is a consequence of ion-atom interaction and is not due to the beam heating effects, which is termed as ion beam induced epitaxial crystallization (IBIEC). IBIEC has being explored by various researchers as an alternative method for damage recovery of ion implanted single crystalline materials, especially Si. So far IBIEC has been examined for heavy ions of energies in the range of 1–3 MeV. The crystallization is understood to occur by the nuclear energy loss processes, which generate vacan- cies around the interface. The possible role of electronic energy deposition on the crystallization process has been reported in case of silicon-on-insulator structures [8], which indirectly suggests that swift heavy ion (SHI) irradiation through an amorphous/crystalline (a/c) interface causes 0168-583X/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2007.01.008 * Corresponding author. Address: Instituut voor Kern-en Stralingsfysica and INPAC, KU Leuven, B-3001 Leuven, Belgium. Tel.: +32 16 32 7514; fax: +32 16 32 7985. E-mail addresses: pratap.sahoo@fys.kuleuven.be, vnk@iitk.ac.in (P.K. Sahoo). www.elsevier.com/locate/nimb Nuclear Instruments and Methods in Physics Research B 257 (2007) 244–248 NIM B Beam Interactions with Materials & Atoms