raman mapping

**Raman Mapping** is a **technique that records Raman spectra at each pixel across a sample surface** — building spatial maps of composition, crystallinity, stress, phase, and molecular species from the variation of Raman peak positions, intensities, and widths. **How Does Raman Mapping Work?** - **Scan**: Raster the laser spot across the sample on a predefined grid. - **Spectrum**: Record a full Raman spectrum at each pixel. - **Analysis**: Fit peaks, extract positions/widths/intensities, and generate false-color maps. - **Resolution**: Diffraction-limited (~0.5-1 μm) spatially, ~1 cm$^{-1}$ spectrally. **Why It Matters** - **Stress Mapping**: Raman peak shifts map mechanical stress in silicon devices (e.g., near TSVs, STI edges). - **Phase Identification**: Different crystal phases (amorphous, polycrystalline, crystalline) have distinct Raman signatures. - **Composition**: Maps alloy composition (SiGe), carbon nanotube chirality, and molecular species. **Raman Mapping** is **chemical imaging through vibrations** — using Raman spectroscopy at every pixel to map composition, stress, and structure.