In this work freestanding silicon nanostructures with high aspect ratio are fabricated using a chemical-electrochemical etching technique. <;100> silicon samples first are textured, covered with hillocks with pyramid shapes via anisotropic wet etching of the samples in TMAH/IPA solutions. Effects of various combinations of TMAH/IPA on the pyramidal texture of silicon are studied in detail. Then, the textured silicon samples are subjected in an electrochemical etching in HF/Ethanol solution to form the nanostructures. A third step of fine etching of the samples in diluted TMAH/IPA solutions was necessary to remove residual and un-etched walls between the structures. Effect of various fabrication parameters controlling the length and tip-to-tip separation of the final structures are investigated. Potential applications of the fabricated structures are remarked.