Germanium tin (Ge1-xSnx) is one of the most promising materials for various types of electronic devices, optoelectronic devices and so on. From the application view point, the stress induced in the Ge1-xSnx significantly modifies the band structure, therefore affects both the electric and optical performances. Moreover, the stress in the actual device is typically in complicated anisotropic biaxial manner rather than simply isotropic or uniaxial. However, it is difficult to evaluate the precise stress states. In this study, we investigated the dependence of pattern size of the Ge1-xSnx mesa structure on the anisotropic biaxial stress by oil-immersion Raman spectroscopy. We verified that stress relaxation progresses sufficiently due to the nano-fabrication process. From the results, it was confirmed that the behavior of uniaxial stress relaxation in the Ge1-xSnx mesa structure is depending on the pattern size.
- Biaxial stress
- Germanium tin
- Metal-organic chemical vapor deposition
- Oil-immersion Raman spectroscopy