ERDA - Elastic Recoil Detection Analysis

ERDA (Elastic Recoil Detection Analysis) method is based on the energy analysis of ions ejected from the target by fast incoming ion projectiles. This is a complementary method to RBS. It allows measuring depth profiles of light elements in the sample (hydrogen in particular), because projectile ion is more massive than the atoms whose concentrations we would like to determine. In experimental setup for ERDA the incident ions hit the sample under small angle with respect to the surface and the ejected ions are analyzed in the forward direction. To separate projectile ions from the ejected a thin carbon or aluminium foil is placed in front of the detector to stop the heavier ions. By ERDA method we can reach depth profiles up to 0.5 µm with resolution 30-40 nm. The sensitivity is about 0.1 atomic % for hydrogen. Incident beams of He and Li ions are used for depth profiling of H or D.

TOF-ERDA was developed and is available in MIC. In this set-up the energy and time-of-flight (i.e. velocity) of the ejected ions are simultaneously measured. On this way depth profiles of many elements in the sample are measured simultaneously. Some heavier ions are usually used as projectiles in this method. For example, by using ions of Cl in the probe beam we can see in TOF-ERDA spectrum contributions of all elements lighter than Si that are present in the target sample.

ERDA method is used on our microbeam and ERDA/RBS beamline.

Last updated: 01/22/2014