This paper describes the elaboration of high aspect ratio (250), high linear density (500 cm 1) suspended silicon nanobridges into low concentrated alkaline solutions. Trenches were first etched into silicon using the deep reactive ion etching STiGer process. These structures were immersed into low concentrated potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH) solutions. The behaviors of KOH and TMAH as silicon trenches etching agents (kinetic and quality of etching) were studied to optimize the silicon nanowires (SiNWs) formation and the elaboration of the suspended structures. The limits of the SiNWs thickness in these conditions were also discussed.