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ANNEALING KINETICS DURING RAPID AND CLASSICAL THERMAL PROCESSING OF LASER AND IMPLANTATION INDUCED DEFECTS IN SILICON W.O. ADEKOYA, J.C. MULLER and P. SIFFERT Centre de Recherches Nucl~aires (IN2P3) Laboratoire PHASE (UA du CNRS no 292) 23, rue du Loess F - 67037 STRASBOURG CEDEX (FRANCE) ABSTRACT The annealing behaviour of electrically-active defects induced in virgin n-type silicon by-Nd-Yag Laser (1.6 J cm-, 2 0.53 pm) irradiation has been investigated with Deep Level Transient Spectroscopy (DLTS). The observed defects : E(O.32 eV), E(0.45 eV) and E(O.53 eV) are characteristic of laser treated silicon, and have been reported by a number of workers. Using a rapid thermal furnace at 600'C for durations between 10 and 60s, we have observed a linear decrease in the concentration of these defects, and for times T > 60s, they are seen to disappear. A similar result was obtained in studies carried out on both virgin and implanted p-type silicon. This is in sharp contrast to the classical furnace annealing which requires much longer durations (20-30 min) at the same temperature (600 0 C) in order to obtain the same results. A study of the annealing kinetics for the E(O.32 eV ; cr = 8 x 10-16 cm- 2 ) level between 500 and 6501C in steps of 50 0 C for the two processes confirms this tendency for all processing temperatures, and shows a difference in activation energy of practically the same order of magnitude as the ionization energy of the defect0 (i.e. = 0.31 eV). Induced defects in high temperature > 1000 C in rapid thermal processed (RTA) n-type Si, also annealed out after a further 600-650 0 C, 60 s RTA treatment. These results suggest that defect annealing is not a purely thermal mechanism, and lend strong support to the idea of an ionization induced enhancement. INTRODUCTION The doping of semiconductors by ion implantation (1) followed by thermal processing for the regrowth of the amorphized layer and the electrical activation of implanted dopants (2) has emerged in recent years as an interesting and alternative technology for the microelectronic industry. Substitutional dopant concentrations exceeding conventional solubility limits have been observed in laser-annealed ion-implanted silicon (3). However, the need for a post-laser thermal treatment for the annealing of the residual defects due to the implantation or even to the laser processing itself, results in a fall of the initial very high activation level obtained after the laser treatment, due to0 long processing durations (= 30 mins) at a temperature 2600 C in a classical furnace for the removal of such defects. Even the recently introduced rapid thermal annealing technique is known to induce defects in silicon (4) in spite of its advantage of high dopant activation (> 90%) with negligible redistribution, and such defects induced by RTA or residual due to the implantation seriously limit device performance. It is the aim of this work, to study the possibility of annealing such Mat. Res. Soc. Symp. Proc. Vol. 74. c1987 Materials Research Society

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