Local anodic oxidation by atomic force microscopy for nano-Raman strain measurements on silicon–germanium thin films

Nanolithography based on local anodic oxidation (LAO) by atomic force microscopy is a promising technique for patterning strained film nanostructures on the silicon substrates. Due to its versatility and precise control, LAO is suited for preparing well defined calibration structures for local strain measurements. We investigated silicon–germanium patterns prepared by LAO and subsequent selective anisotropic wet etching. By combining the nanolithography and etching, dedicated strain test structures with a line width of 65 nm were achieved and utilized for calibration of tip-enhanced Raman measurements.