Spectroscopic ellipsometry device and method based on elasto-optical modulation

Abstract

The invention relates to the technical field of ellipsometry methods and instrument equipment, in particular to a spectroscopic ellipsometry device and method based on elasto-optical modulation. Achievement of the spectroscopic ellipsometry device and method is based on 45-degree dual-drive symmetrical structure elasto-optical polarization modulation and a FPGA elasto-optical drive control and data signal treatment technology. After a compound color light source outputs quasi-monochromatic light through a monochromator, through light speed shaping and collimation, the light exits from an analyzer and is detected and received by a photomultiplier after passing through a polarizer, a to-be-measured sample and an elasto-optical modulator. In an FPGA unit, cophase component and orthogonal component demodulation of a modulated optical signal frequency doubling item is achieved, and the introduction into a control computer is achieved; the spectroscopic ellipsometry device does not need mechanical adjustment, the measuring speed is high, the precision and the sensibility are higher, automatic control is convenient, and a new theory and a new method can be provided for relative fields ofthe spectroscopic ellipsometry technology.

Description

technical field [0001] The present invention relates to the technical field of ellipsometric measurement methods and instruments, and more specifically, to a spectral ellipsometric measurement device and method based on elasto-optic modulation. Background technique [0002] Ellipsometry technology can realize the measurement and analysis of parameters such as optical constants (refractive index n, extinction coefficient k), film structure, roughness and thickness of thin film samples by measuring the polarization state change before and after polarized light enters the sample. It has been widely used in the fields of optical window coating, microelectronics, photovoltaic solar cells, semiconductor materials and photoelectric display, and has gradually shown its application potential in high-tech fields such as life sciences, nanotechnology, and new material technology. With the deepening of scientific and technological exploration, the intersection and integration of differe...

AI Technical Summary

Problems solved by technology

However, whether it is a rotating polarizer type ellipsometer or a rotating compensator type ellipsometer, the measurement rate is limited by the rotation rate of the stepping motor, and the single measurement time is on the order of seconds, which makes it impossible to achieve high-speed ellipsometric measurement; And the mechanical rotation of the polarizing element will cause the beam to shift, and the system stability will be reduced, so that the measurement accuracy cannot be guaranteed

The elastic-optical modulation type ellipsometer has application advantages such as fast measurement and high sensitivity, and is an important development direction of high-speed ellipsometry technology. However, due to the fixed fast axis during the use of traditional PEM, it is impossible to achieve a complete analysis of the polarization state of the detected light. Furthermore, the ellipsometer using a single PEM cannot realize the full range measurement of ellipsometric parameters

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