Determination of the Base-Dopant Concentration of Large-Area Crystalline Silicon Solar Cells

The capacitance-voltage (CV) measurement is a precise and fast method to determine base-dopant concentrations of crystalline silicon solar cells. Since available measurement equipment is usually limited in its current output, the application of CV analysis has been limited to small-area solar cells in research laboratories. We present an experimental setup that is capable of measuring CV curves with a current output of up to 2 A. Using this setup, we demonstrate the applicability of CV measurements to large-area industrial solar cells for base-dopant concentrations ranging between 6.0 × 10¹⁴ cm^-3 and 4.2 ×10¹⁶ cm^-3. An area enhancement factor f quantifying the relation between the macroscopic cell area and the active junction area is determined for alkaline textured mono- and isotextured multicrystalline silicon solar cells. Comparing the base dopant of the CV analysis with four-point probe measurements, we achieve an agreement with an uncertainty of 10%. For alkaline textured monocrystalline silicon solar cells, we demonstrate that the area enhancement factor can be extracted from the ratio of the pyramid base length and emitter thickness.