Mechanical stress in silicon nanosized architectures: Defects of SOD processed silica filler

• Structural and optical properties of silica filled STI architectures.
• The silica filler induces a compressive stress.
• PL spectra show a large distribution of emitting defects in the UV–blue.
• The defects were identified and located at the silica–liner interface.

The mechanical stress in nanosized silicon architectures is studied in shallow trench isolation systems with different liners and spin on dielectrics processed silica filler by means of Raman spectroscopy. The nanopatterning of silicon wafers causes a tensile stress of the system whereas the presence of the filler induces a compressive stress which depends on the interaction between silica filler and liner: by changing the liner from silicon dioxide to silicon nitride one can induce a larger compressive stress. The analysis of the ultraviolet excited emission properties in the visible range (nanosecond lasting bands at 2.5, 3.0 and 3.3 eV) allowed us to individuate and locate silica related defects and to correlate their presence to the induced compressive stress.