Nanosized lead inclusions in silicon produced by ion implantation

Silicon single crystals have been implanted with 80 keV lead ions to a conc entration of about 3 at.%. TEM and RBS/channeling analysis showed that impl antations at 300 and 625 K induced amorphization of the implanted layer wit h nanoscale lead inclusions embedded in the amorphous matrix. At 300 K; the lead inclusions had sizes around 1-2 nm and showed no clear signs of cryst allinity. At 625 K the inclusions with size around 5 nm had a distinct fee structure and were oriented randomly in the amorphous matrix. Implantations at 925 K retained the crystalline nature of the matrix and the implanted l ayer contained faceted fee lead inclusions about 10 nm in size growing in p arallel-cube alignment with the matrix. Annealing of the samples implanted at 300 and 625 K, respectively, for one hour at 1175 K led to recrystalliza tion of the amorphous matrix with simultaneous loss of nearly all the impla nted lead, while about 80% of the implanted lead was retained after anneali ng of samples implanted at 925 K. (C) 1999 Elsevier Science B.V. All rights reserved.