Spatially Resolved Analysis of Selectively Doped Regions via Confocal Raman Microscopy

More or less all proposed highly efficient solar cell concepts use quite successfully laterally selective boron doping. However, quality control regarding achieved doping level, lateral extension, etc. on real devices or precursors gets more and more complicated with these small structures as the typical characterisation techniques simply do not work well on small scale. High resolution mapping confocal Raman spectroscopy is considered a possible technique to tackle this challenge. In this contribution it is demonstrated on IBC precursor structures that the contrast in local doping level can be finely resolved via mapping Raman spectroscopy, even though the determined absolute value is found to be too small. It is discussed on the basis of a few fundamental calculations that the depth sensitivity is accountable for this drawback.