Dual-lens electron holography for junction profiling and strain mapping on semiconductor devices

Abstract

Dual-lens electron holography with a wide range of FOV and spatial resolution for semiconductor device junction profiling and strain mapping is reported. The method has the advantage of allowing the fringe width and fringe spacing in electron holograms to be adjusted independently from the fringe contrast. This results in better spatial resolution and signal-to-noise for the characterization of semiconductor devices of 2-D potential profiling and strain mapping. Through high-spatial-resolution mapping with dual-lens electron holography, significant insight into device characteristics is revealed. An example shows that a shallow junction device is not a stable device without raised source/drain technology. For strain measurement with dark-field dual-lens electron holography at high spatial resolution, Another example shows that the strain for sigma-shaped SiGe is concentrated in the channel region. One more example provides strong experimental evidence that tensile strain of the stress memorization process is memorized in the dislocation of the source/drain silicon region for nFETs.