Springer Online Journal Archives 1860-2000
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Abstract We have investigated the annealing behaviour of electrically-active defects induced in virgin n-type and residual in As+ implanted p-type silicon after laser irradiation, using the rapid thermal annealing technique (RTA). Spectra from deep level transient spectroscopy (DLTS) show that three majority carrier traps at E (0.32 eV), E (0.45 eV) and E (0.53 eV) were induced in the n-type Si after Nd-Yag laser treatment at 1.6 J cm−2. Annealing in a rapid thermal furnace at 600 °C for times between 5 and 60 s resulted in a linear decrease of the concentration of these defects and for times ≧ 60 s, they are no longer detectable. A similar result was obtained in the case of the multiple energy As+ implanted samples in which two majority carrier traps at H (0.30 eV), H (0.58 eV) and a minority carrier trap E (0.53 eV) completely disappeared after annealing for 45 s at 600 °C, in spite of the very high concentration of the H (0.58 eV) defect (〉1015 cm−3 up to a depth of about 1.5 μm). A comparison of the annealing rates of the E (0.32 eV) trap using the RTA and the conventional thermal annealing (CTA) techniques at 600 °C showed that the former is at least 30 times faster than the latter. Sheet resistance measurements show that the level of dopant deactivation, due to post-laser thermal treatment at 500 °C (in order to obtain the same reduction in residual defect concentration), is less in the RTA processed samples than in those annealed using conventional methods. These results lend strong support to the hypothesis of ionization-induced enhancement of defect annealing, and to our knowledge, represent the first report of the observation of the phenomenon using the RTA technique.
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