Fig. 2From: Optimization of deep reactive ion etching for microscale silicon hole arrays with high aspect ratioSEM cross-sectional images of hole arrays with various diameters a 0.79 μm, b 1.09 μm, c 1.49 μm and d 1.90 μm) after 60 DRIE cycles with the standard DRIE recipe. SEM cross-sectional image of trench array with a width of e 0.74 μm. f Etch depth and g area reduction ratio as a function of hole diameter or trench width. All scale bars are 2 μmBack to article page