Digital circularly polarized heterodyne ellipsometer

In this research, a digital circularly polarized heterodyne ellipsometer (DCPHE) is developed, which has a heterodyne interferometer based on a dual-frequency paired circularly polarized laser beam integrated with a digital storage oscilloscope. DCPHE is an amplitude-sensitive ellipsometer that is applicable to real time and precise measurement of ellipsometric parameters. The systematic errors are likewise derived and analyzed. When the incident angle α are set at 60° and 70° in DCPHE, an accuracy of less than 0.7% of the ellipsometric parameter measurement of the SiO2 thin film deposited on silicon substrate is achieved.