半导体特性的调制自由载流子吸收变距频率扫描方法研究

根据调制自由载流子吸收（modulated free carrier absorption，MFCA）检测技术的三维理论模型，采用变间距频率扫描方式测量单晶硅样品的电子输运参数，进行了仿真与实验，对结果进行了分析；通过多参数拟合，获取了测试样品的载流子扩散系数、少数载流子寿命和前表面复合速度.仿真与实验都表明，变间距频率扫描结合多参数拟合，可以提高输运参数的测量精度. 关键词： 调制自由载流子吸收 电子输运参数 变间距频率扫描 多参数拟合

Modulated free carrier absorption characterization of semiconductor wafers by frequency scans at different pump-to-probe separations

Based on a three-dimensional modulated free carrier absorption （MFCA） model，simulation was performed to investigate the dependences of MFCA amplitude and phase on the electronic transport properties （the carrier lifetime，the carrier diffusivity，and the front surface recombination velocity） of semiconductor wafers at different pump-to-probe separations and different modulation frequencies. Experiments were performed with a silicon wafer，in which amplitude and phase were recorded as functions of modulation frequencies at several different two-beam separations. The electronic transport properties of semiconductor wafers were determined simultaneously via multi-parameter fitting procedure. These results showed that the method is capable of improving the measurement precision of the simultaneous multi-parameter determination of transport properties.