|Multicrystalline silicon (mc-Si) is material,
especially produced for solar cell application. The following figure show the
prototype ELYMAT in our lab for measuring the square mc-Si wafer.
The problemes for measuring mc-Si with the ELYMAT technique are especially due to the :
|high leakage currents and|
|the high breakage facility|
|of this material.
|The figure at the left side shows a typical
"ELYMAP" of a mc-Si wafer. The dark colors (black, blue) can
be interpreted as poor diffusionlengths (55 µm), the light colors
(yellow, red) are representing better diffusionlengths (115 µm). The
grains and grain boundaries are quite obvious.
The solar-ELYMAT ist able to measure 85mm x 85mm square multicrystalline wafers. In standard mode, we use a stepsize of 1/5 mm, this leads to ELYMAPs with 510 x 510 pixels. For high resolution measurements a minimum stepsize of 20 µm is possible (for zoom-maps of small areas).