光腔衰荡法对腔内介质吸收有着极高的测量灵敏度，可实现腔损耗的精确测量。本文基于自由载流子吸收理论和谐振腔理论，建立了半导体材料特性测量的光腔衰荡理论模型，推导了腔衰荡信号与半导体材料特性参数和光学谐振腔结构参数间的函数关系，并进行了仿真分析和实验验证。仿真结果表明：光腔衰荡法可以实现半导体材料特性的精确测量，如掺杂浓度和电阻率。同时，基于该技术对半导体单晶硅片掺杂浓度和电阻率进行了实验测量，结果分别为(2.65±0.38)×1016cm-3和(0.61±0.07)Ω?cm，说明该方法在半导体材料特性测量中具有很好的应用潜力。

The cavity ring-down method has an extremely high measurement sensitivity to the absorption of a medium in the cavity and can be used to accurately measure cavity loss. Based on the theories of free carrier absorption and resonant cavity, this study establishes a theoretical model of an optical cavity ring-down to measure the properties of semiconductor materials and derives the functional relationship among the cavity ring-down signal, semiconductor material characteristic parameters, and cavity structure parameters. Simulation analysis and experimental verification are performed. Simulation results show that the cavity ring-down method can be used to accurately measure semiconductor material properties, such as doping concentration and resistivity. Meanwhile, based on the proposed method, the doping concentration and resistivity of a crystalline silicon wafer are determined experimentally to be (2.65±0.38)×1016cm-3 and (0.61±0.07)Ω?cm respectively, exhibiting the high application potential of this method for measuring semiconductor material properties.