Depth profile analysis of helium in silicon with high-resolution elastic recoil detection analysis

Abstract

Helium depth profiling in silicon was investigated by high-resolution elastic recoil detection analysis (HERDA) using a high-resolution Rutherford backscattering spectrometry system. A 0.7 μm Mylar film was installed in front of the detector of this system to eliminate the background signals originating from incident nitrogen ions scattered at the sample surface. This film successfully eliminated the background signals without the loss of helium signals or serious degradation of the depth resolution. The HERDA has several attractive features for helium depth profiling in silicon, including high sensitivity (detection limit of 1 at. % or less), excellent depth resolution (less than 1 nm), and good quantitative accuracy, giving it significant advantages over other surface analysis methods such as secondary ion mass spectrometry.