Study of stress in a shallow-trench-isolated Si structure using polarized confocal near-UV Raman microscopy of its cross section

Stress in shallow-trench-isolated structures with 250-nm-wide Si stripes was examined by 364nm excitation confocal Raman microscopy. Using objective lenses with the experimentally measured ∼150nm spatial resolution, we studied polarized Raman spectra from the section perpendicular to the stripes. Detection of two optical phonons enabled us to analyze orientation and intensity of local stress quantitatively. Uniaxial [001] compressive stress was found in the Si substrate under both the trench and the stripe, while the stress in the stripe was uniaxial [110] perpendicular to the stripe.