Annealing Kinetics during Rapid and Classical Thermal Processing of Laser and Implantation Induced defects in Silicon

Abstract

AbstractThe annealing behaviour of electrically-active defects in-duced in virgin n-type silicon by-Nd-Yag Laser (1.6 J cm−2,0.53 μm) irradiation has been investigated with Deep Level Transient Spectroscopy (DLTS). The observed defects : E(0.32 eV), E(0.45 eV) and E(0.53 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 vir-gin and implanted p-type silicon. This is in sharp contrast to the classical furnace annealing which requires much longer du-rations (20–30 min) at the same temperature (600 °C) in order to obtain the same results. A study of the annealing kinetics for the E(0.32 eV ;σn = 8 × 10−16 cm−2) level between 500 and 650°C in steps of 50°C for the two processes confirms this tendency for all processing temperatures, and shows a difference in ac-tivation energy of practically the same order of magnitude as the ionization energy of the defect (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 °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.