Determination of size and density of embedded Ge nanocrystals in SiO2 by scanning force microscopy using a tomographic approach

Abstract

Germanium nanocrystals in silicon dioxide were studied by atomic force microscopy (AFM) to reveal their size, density and distribution. The generation of the nanocrystals was accomplished by Ge+ ion implantation into a 100‐nm silicon dioxide layer and subsequent annealing at high temperatures in an inert atmosphere. Rutherford backscattering spectroscopy was applied to reveal the Ge distribution after implantation and annealing, and the formation of the nanocrystals was proven by transmission electron microscopy. The oxide layer was gradually etched to uncover the nanocrystals located at different depth positions within the SiO2 layer. Subsequently, the unveiled surfaces were examined by AFM in order to determine the size and density of the exposed nanocrystals. A correlation between the nanocrystal properties and the Ge implantation dose was corroborated. Copyright © 2012 John Wiley & Sons, Ltd.