Stress redistribution in individual ultrathin strained silicon nanowires: a high-resolution polarized Raman study

Strain nano-engineering provides valuable opportunities to create high-performance nanodevices by a precise tailoring of semiconductor band structure. Achieving these enhanced capabilities has sparked a surge of interest in controlling strain on the nanoscale. In this work, the stress behavior in ultrathin strained silicon nanowires directly on oxide is elucidated using background- free, high-resolution polarized Raman spectroscopy. We established a theoretical framework to quantify the stress from Raman shifts taking into account the anisotropy associated with the nanowire quasi-one-dimensional morphology. The investigated nanowires have lateral dimensions of 30, 50 and 80nm and a length of 1µm top-down fabricated by patterning and etching 15nm thick biaxially tensile strained silicon nanomembranes generated using heteroepitaxy