Speaker:Dr. Zhu Zihua, Scientist II & III, Environmental Molecular Sciences

Date:April 8, 2014

Time:2:00 p.m.

Location:Lecture Hall, School of Physics, Central Campus

Sponsor:School of Physics

Abstract:

Rutherford backscattering (RBS) and other ion beam-related analysis techniques (e.g., elastic recoil detection analysis (ERDA) and nuclear reaction analysis (NRA)) have been among the most popular techniques to characterize the depth profile of implanted ions. However, RBS has several limitations. For example, (1) it is difficult to distinguish elements with similar masses (e.g., 90Zr in SrTiO3), and (2) it is hard to measure light elements in high mass matrix. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used in characterizing depth distribution of implanted ions for more than twenty years. Compared to RBS, ToF-SIMS has several unique advantages. First, ToF-SIMS can provide high mass resolution (M/DM > 10000), so mass interference is normally not a problem. Second, 10 microns depth profiling is feasible for ToF-SIMS, but RBS can only go 1-2 microns deep. In addition, depth resolution of ToF-SIMS can go down to sub-nanometer, and sensitivity of ToF-SIMS is approximately 1-3 orders of magnitude better than RBS (element dependent), which make ToF-SIMS one of the best tools for performing ultra-shallow depth profiling. The major drawback of ToF-SIMS depth profiling is quantification. Matrix effect makes SIMS quantification not straightforward. Therefore, ToF-SIMS and RBS can be regarded as complementary techniques in characterizing depth distribution of implanted ions. Interesting results have been demonstrated when combining these two analytical techniques. In this talk, several representative examples will be presented and discussed.

For further information, please visit:http://www.phym.sdu.edu.cn/2014/0407/3019.html