Development of calibration-free imaging ellipsometry using dual-rotation of polarizer and analyzer

Abstract

Imaging ellipsometry is developed in the dual-rotation mode of a polarizer and an analyzer. In this system, the polarizer and analyzer are rotated by a stepping motor at 1 : 1 ratio and the offset between the azimuths of both elements is kept constant. For data reduction, a two-dimensional array detector collects multiple intensity images during rotation and waveform analysis is performed for each pixel. This system generates second and fourth harmonics in intensity waveform and {A, psi} images are deduced from the amplitudes of these harmonics without considering their phases, which leads to calibration-free imaging ellipsometry. This system works well with an offset between two elements but it becomes less susceptible to an offset-setting error with a smaller offset. Besides the ease of operation, this system is simple to construct as no complicated control mechanism is required for each component.