Ricerc@Sapienza

Localized strained silicon was observed with a suitable resolution in a real semiconductor device
by tip-enhanced Raman spectroscopy (TERS). The device was made via a standard industrial process
and its silicon trench isolation structures were used for the silicon strain analysis obtaining
results according to finite element method-based simulation data. We have achieved a reliable and
repeatable enhancement factor obtaining a trace of strained silicon along the structure with suitable
nanometer spatial resolution compatible with IC industry requirements. We demonstrate that the
complexity to analyze a real 3D structure, directly from the production lines and not ad hoc realized,
entails the challenges to individuate the optimal tip shape, tip contact angle, tip composition,
tip positioning system, laser power, and wavelength to achieve an appropriate plasmon resonance
inducing a relevant signal to noise ratio. This work gives the base to address the development in
TERS optimization for real industrial applications.