Wednesday, February 15, 2017

Abstract-Simultaneous measurement of doping concentration and carrier lifetime in silicon using terahertz time-domain transmission

M. Lenz1C. Matheisen2M. Nagel2, and J. Knoch1

In this work, we present a measurement approach enabling the simultaneous determination of sheet resistance and carrier lifetime in semiconductor samples. It is based on a classic Terahertz (THz) time-domain transmission spectroscopy scheme extended by quasi-steady state optical excitation. The carrier lifetime is determined by contactless THz probing of the increase in sheet conductance associated with quasi-steady-state excitation. Combining a successive etch-back of the surface with repeated THz measurements yields a depth profile of the doping concentration and the carrier lifetime, which is important for the optimization of the emitter of solar cells, for instance. The viability of our approach is demonstrated by investigating a phosphorous doped emitter of a silicon solar cell with the THz approach and comparing the results with electrochemical capacitance voltage measurements.

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