Raman Imaging
Avacta has extensive experience of physico-chemical mapping of surfaces using Raman imaging and Raman microscopes with a range of excitation wavelengths. Example applications of Raman imaging are stress mapping in semiconductors and mapping the distribution of polymorphic forms in pharmaceutical tablets.
Residual Stress in Damaged Silicon Wafer
Sample: Damaged silicon wafer
Motivation: Residual stress in silicon can affect its electrical properties and causes problems during IC fabrication.This becomes more important as device sizes decrease.
Fig. (a) Raman map showing distribution of crystalline silicon as characterised by 520 cm-1 Raman band, (single point spectrum shown in fig. (d))
Fig. (b) Residual Stress map as characterised by shift in ~520 cm-1 Raman band, (single point spectrum shown in fig. (e)).
Fig. (c) Raman map showing distribution of amorphous silicon as characterised by ~300/450 cm-1 Raman band (fig. (f))