Watkins Lionel R
Department of Physics, University of Auckland, P.B. 92019, Auckland, New Zealand.
Appl Opt. 2009 Nov 10;48(32):6277-80. doi: 10.1364/AO.48.006277.
A new approach to automatic null ellipsometry is described in which the analyzer of a traditional polarizer compensator sample analyzer (PCSA) null ellipsometer is replaced with a heterodyne Michelson interferometer. One arm of this interferometer is modified such that it produces a fixed, linearly polarized reference beam, irrespective of the input polarization state. This beam is recombined interferometrically with the measurement beam and spatially separated into its p and s polarizations. The relative phase of the resulting temporal fringes is a linear function of the polarizer azimuthal angle P, and thus this component can be driven to its null position without iteration. Once at null, the azimuthal angle of the reflected, linearly polarized light is trivially determined from the relative amplitude of the fringes. Measurements made with this instrument on a native oxide film on a silicon wafer were in excellent agreement with those made with a traditional PCSA null ellipsometer.
本文描述了一种自动消光椭偏仪的新方法，其中传统的偏振器 - 补偿器 - 样品 - 分析器（PCSA）消光椭偏仪的分析器被外差迈克尔逊干涉仪所取代。该干涉仪的一个臂经过修改，使得无论输入偏振态如何，它都能产生固定的线偏振参考光束。该光束与测量光束进行干涉重组，并在空间上分离为其p偏振和s偏振。所得时间条纹的相对相位是偏振器方位角P的线性函数，因此该分量可以无需迭代地驱动到其消光位置。一旦处于消光状态，反射的线偏振光的方位角可从条纹的相对幅度轻松确定。用该仪器对硅片上的原生氧化膜进行的测量与用传统PCSA消光椭偏仪进行的测量结果非常吻合。
