Dual-Lens Electron Holography for Junction Profiling and Strain Mapping on Semiconductor Devices

Abstract

Abstract IBM engineers have developed a holographic imaging technique, called dual-lens electron holography, that provides high spatial resolution and field of view without compromising signal-to-noise ratio. This article reviews the basic principles of the new method and provides several examples of its use. The first few examples demonstrate the junction profiling capabilities of the new method which, in one case, helps to explain why shallow junction devices are made with raised source-drain regions. In the other examples, dual-lens holography is used for strain mapping, in one case, to study strain distributions in sigma-shaped SiGe devices, and in another, to provide evidence that stress memorization occurs in dislocations in the source-drain region of nFET devices.