PSA簡式橢圓儀

Abstract

我們將介紹一PSA亮度式橢圓偏光儀,並用以量測樣品之橢圓偏極參數 psi 和delta.當入射光之平行與垂直入射面的亮度相等時,其反射光的偏振變 化則完全取決於樣品之光學特性.我們將證明在此偏振態下只須量測三個 亮度即可推算橢圓參數,並證明利用入射光之偏振態在負四十五度所得之 結果可優化所測得之橢圓參數.本論文用測得之橢圓偏極參數psi和delta, 推算白金和二氧化矽鍍於矽上之薄膜之厚度及折射率,所得之結果並與其 它已有資料比較,誤差約在0.5%之內. A PSA photometric ellipsometer is introduced to measure the ellipsometric parameters psi and delta of a sample. If the field of the parallel(p) and perpendicular(s) to the plane of incident are equal, the change of the state of the pol- arization of reflected light are affected by the optical properties of sample. We will prove that only three radiances through equally spaced polarizer are needed for extracting the parameters. The results are improved by deducing measure- ments from the incident light that is linear polarized at -45(deg) to the plane of incident. The measued parameters psi and delta are used to calculate the refractive index for Pt, the thickness of thin film for SiO2 coating on Si. By comparing all the available sources, we find that our experimental error are less then 0.5%.