Raman spectroscopy is an indispensable method for the nondestructive testing of semiconductor materials and their microstructures. This paper presents a study on the angle-resolved intensity of polarized micro-Raman spectroscopy for a 4H silicon carbide (4H-SiC) wafer. A generalized theoretical model of polarized Raman intensity was established by considering the birefringence effect. The distributions of angle-resolved Raman intensities were achieved under normal and oblique backscattering configurations. Experiments were performed on a self-built angle-resolved Raman system, which verified the validity of the proposed model and achieved the identification of crystal orientations of the 4H-SiC sample.

Polyethylene terephthalate (PET) is one of the most commonly used substrate materials in the field of flexible electronics, and its stress-induced birefringence often has a detrimental effect on the optical properties of the device. Therefore, a deep and systematic understanding of the stress-optical properties of PET films is crucial for device design and manufacture. The photoelastic method is a direct optical measurement technique based on the stress-induced birefringence effect of materials, which has the advantages of being nondestructive and noncontact. In this work, the photoelastic method was used to quantitatively characterize the anisotropy of the stress-optical properties of PET films under the uniaxial stress state. First, a self-built reflection-transmission coaxial bidirectional photoelasticity measurement system was developed by means of a combination of transmission and reflection photoelasticity. Then, the stress-optical coefficients and isoclinic angles of PET films with different stretching angles were measured. Finally, the linear combinations of the photoelastic tensor components and refractive-index-related parameters were determined by fitting the analytical relationship between the stress-optical coefficients and isoclinic angles.