Study of two-dimensional B doping profile in Si fin field-effect transistor structures by high angle annular dark field in scanning transmission electron microscopy mode

Abstract

High angle annular dark field in scanning transmission electron microscopy mode is used to characterize the two-dimensional B dopant profile of Si fin field-effect transistor nanostructures. We attribute the enhanced intensity in the images to the strain fields produced by the substitutional B atoms in the Si lattice. Two different doping cases were studied, with an increment in the ion dose level. The observed doping profiles were compared with scanning capacitance microscopy images and with computer simulations of the same structures. All results show excellent qualitative agreement. High resolution transmission electron microscopy, electron energy-loss spectroscopy, and energy-dispersive spectroscopy analyses were also performed on these samples and were instrumental in identifying Cu nanoparticle contamination in the prepared transmission electron microscopy samples.