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Laser Thermal Annealing (LTA) in conjunction with ion implantation has been demonstrated to be a very effective method to achieve heavily doped and localized regions needed in both advanced MOSFET and solar cells technology. In some cases, degradation of the electrical properties of the laser doped regions has been reported, including increased leakage current in pn junctions, reduced carrier mobility and breakdown voltage shift in MOS transistors [1] or reduced carrier lifetime in solar cells [2], which are attributed to laser-induced damage, including impurity penetration during anneal [3] or point defect generation during melt recrystallization [4]. However, few works have been focused so far on the detailed investigation of laser induced damage. In this work, we present a comprehensive investigation of laser induced damage by implementing a methodology allowing the identification and the localization of the defects as well as the investigation of their impact on the properties of the annealed regions. In order to avoid additional damage generated during an implant step, the investigations were conducted on in-situ doped Si substrates. Excimer LTA (λ= 308 nm, pulse duration= 160 ns) was carried out with energy densities ranging from 1.7 to 8 J/cm² and with one more multiple pulse conditions. Several experimental parameters were analyzed, including the substrate temperature during LTA (300 or 448 K), the annealing ambient (air or N2) and the surface preparation (HF cleaning, thermal oxide). The annealed samples were analyzed by photoluminescence spectroscopy (PL) with several excitation wavelengths to probe different depths …
Publication date: 
16 Sep 2018

Richard Monflier, H Rizk, Toshiyuki Tabata, Julien Roul, Éric Imbernon, Simona Boninelli, M Italia, Antonio Magna, Fulvio Mazzamuto, P Acosta, S Kerdilès, Fuccio Cristiano, Eléna Bedel-Pereira

Biblio References: 
Pages: 1
22nd International Conference on Ion Implantation Technology