Three-dimensional depth profiles of boron ions implanted in SiO 2

Abstract

Silicon dioxide films were implanted at room temperature with boron ions at 7° and 35°. Implantation energies ranged from 20 to 250 keV and the dose was 5×10 14 ions/cm 2. The depth profiles of ion-implanted boron in SiO 2 were measured using secondary ion mass spectrometry and least-squares fitted to a Pearson distribution. The results demonstrated that the 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 between the measured and calculated values are 4%, 7%, 15%, 22% and 10%, for projected range, longitudinal range straggling, skewness, kurtosis and transversal range straggling, respectively. Rapid thermal annealing (1050°C for 30 s) of the as-implanted specimens revealed that radiation-enhanced diffusion tends to increase projected range, longitudinal range straggling and transversal range straggling, but decrease (in absolute values) skewness and kurtosis. Notably, the increase in transversal range straggling is smaller than that of longitudinal range straggling.