Time domain theory of the electronic transport property of semiconductors measured by means of square-wave-modulated free carrier absorption technique

A time-domain model for the square-wave-modulated free carrier absorption (MFCA) is developed in measuring the electronic transport properties (the carrier lifetime, the carrier diffusivity, and the front surface recombination velocity) of semiconductor wafers. The dependences of time-domain MFCA signals on the electronic transport properties at different modulation frequencies are investigated by computer simulation. It is found that there are the high sensitivities of MFCA signal to the individual transport parameter. Furthermore, compared with the results by frequency-domain MFCA, in time-domain MFCA measuring ranges the transport properties can be improved.