Considerable Improvement of Depth Resolution in Auger Sputter Depth Profiling of Polycrystalline Thin Films Using In-situ Sample Preparation Methods

Abstract

Today, one of the important applications of Auger electron spectroscopy in semiconductor material analysis is in-depth profiling of thin films. The sample is eroded by ion bombardment ('sputtering') and the residual surface is analyzed. The depth distributions of the elements are recorded as a function of sputter time. Especially, when sputtering polycristalline thin films, the depth resolution of sputter depth profiling is limited by the sputter yield differences attributed to grains having different crystalline orientations relative to the incoming ion beam. If depth profiling is performed on a single grain only, the depth resolution enhences. Here, two in-situ sample preparation methods are used to identify a single grain. It is found either at the sputter crater edge or using an in-situ low-angle cross section.