Prediction of Temperature-Dependent Stress in 4H-SiC Using In Situ Nondestructive Raman Spectroscopy Characterization

Abstract

4H-SiC is widely used in power electronics owing to its superior physical properties. However, temperature-induced stresses compromise the reliability of 4H-SiC power devices in high-temperature applications, warranting precise, and nondestructive stress characterization responsive to temperature variations. Herein, a temperature-dependent predictive model is proposed for analyzing the Raman shift–stress in 4H-SiC. The 4H-SiC epitaxial samples prepared via chemical vapor deposition are characterized using in situ variable-temperature Raman spectroscopy, resulting in a temperature correction factor of approximately −0.021 cm−1 K−1, which is integrated into the conventional Raman shift–stress relationship to assess stress variations induced by temperature variations. The elastic modulus tensor of 4H-SiC at various temperatures determined using molecular dynamics simulations indicates a linear reduction in modulus with increasing temperature. This variable temperature modulus is incorporated into the Raman shift–stress relationship. Furthermore, a finite element method is used for model simplification to perform stress calculations in three axial directions. The experimental results confirm the consistency between calculated and experimental values with a 10% error range under the uniaxial stress condition. The study findings provide valuable insights into assessing stress evolution in 4H-SiC under temperature variations based on Raman spectroscopy, thereby advancing the application of spectroscopic techniques in material stress detection.