Silicon nanowire fabrication of nanoscale dimensions on a single-crystal silicon surface by scanning probe lithography (SPL) and potassium hydroxide (KOH) aqueous wet etching system has proven to be adequate technological processes. Using SPL directly to define patterns on a single-crystal silicon surface showed that the linewidth of ∼50 nm can be further shrunk to ∼20 nm with KOH wet etching and orientation-dependent etching (ODE) processes on (110)-oriented silicon samples. In addition, this lithography technique also showed a great ability to define patterns on fluorocarbon mask layers. This method performed the fine linewidth of silicon nanowires around 20 nm by operating with lower applied voltages and higher scanning speeds (shorter exposure time) with SPL and ODE techniques and KOH wet etching on (100)-oriented silicon samples. These alternative processes provide the capability to fabricate nanoscale structures with high reliability and repeatability for applications in the nanofields.