Three-dimensional range distribution of 400 KeV Nd ions implanted into Si

Abstract

The 400 keV Nd ions were implanted into Si at a variety of tilt angles from 7° to 75°. The range distributions were accurately measured by the TOF-SIMS (Time-of-Flight secondary ion mass spectrometry) method. The results show that the measured range profiles can be represented by Pearson I type distributions which are in the same category as predicted by TRIM (TRansport of Ions in Matter). The first four statistical moments of the Nd-depth distribution, namely range, longitudinal straggling, skewness, and kurtosis, were obtained from the fitted profiles, and compared with the corresponding TRIM calculated values. Results show that the experimentally obtained range profiles are obviously deeper and broader than TRIM'95 (version 95.2) predictions, but very good agreements were obtained between the measured values and TRIM'98 (version 98.10) calculation. The longitudinal and lateral range stragglings for normal incidence were deduced from the angular dependence of the measured range distributions. Based on the range distributions for different angle implantation, the three-dimensional range distribution was reconstructed, and the lateral range straggling was obtained from the three-dimensional distribution and compared with both the predicted TRIM values and the deduced value.