Three-dimensional depth profiles of boron ions implanted in SiO2

Silicon dioxide films were implanted at room temperature with boron ions at 7 degrees and 35 degrees. Implantation energies ranged from 20 to 250 keV and the dose was 5 x 10(14) ions/cm(2). The depth profiles of ion-implanted boron in SiO2 were measured using secondary ion mass spectrometry and leas t-squares fitted to a Pearson distribution. The results demonstrated that t he measured depth profiles are well approximated by Pearson distributions, while the experimentally determined range parameters correspond fairly well to the theoretical predictions yielded by the SRIM (stopping and range of ions in matter) Monte Carlo simulation code. The overall differences betwee n the measured and calculated values are 4%, 7%. 15%. 22% and 10%, for proj ected range, longitudinal range straggling, skewness, kurtosis and transver sal range straggling, respectively. Rapid thermal annealing (1050 degreesC for 30 s) of the as-implanted specimens revealed that radiation-enhanced di ffusion tends to increase projected range, longitudinal range straggling an d transversal range straggling, but decrease (in absolute values) skewness and kurtosis. Notably, the increase in transversal range straggling is smal ler than that of longitudinal range straggling. (C) 2001 Elsevier Science B .V. All rights reserved.