Computer simulations are carried out to investigate the sensitivity of simultaneous determination of three electronic transport properties (carrier lifetime, carrier diffusivity, and front surface recombination velocity) of silicon wafers by modulated free carrier absorption (MFCA) via a multiparameter fitting procedure. The relative accuracy of the transport parameter determination by laterally resolved MFCA (LR-MFCA), in which the amplitude and phase are measured as functions of the pump-probe-beam separation at several modulation frequencies covering an appropriate range, and by conventional frequency-scan MFCA (FS-MFCA), in which only the modulation frequency dependences of the amplitude and phase are recorded, is theoretically analyzed and experimentally estimated by calculating the dependence of the mean square variance on individual transport parameter via a multiparameter estimation process. Simulated and experimental results show that the determination of the transport properties of silicon wafers by LR-MFCA are more accurate, compared with that by FS-MFCA. Comparative experiments are performed with a silicon wafer and the estimated uncertainties of the carrier diffusivity; lifetime and front surface recombination velocity are approximately +/- 3.7%, +/- 25%, and +/- 35% for LR-MFCA and +/- 7.5%, +/- 31%, and +/- 24% for FS-MFCA, respectively.
Chinese Acad Sci, Inst Opt & Elect, Chengdu 610209, Sichuan, Peoples R China
Zhang, Xiren,Li, Bincheng,Liu, Xianming. Accuracy analysis for the determination of electronic transport properties of Si wafers using modulated free carrier absorption[J]. JOURNAL OF APPLIED PHYSICS,2008,104(10).