Hi all, i need to realize a Silicon On Nothing (SON) structure of lateral size about 0.5x0.5mm. Silicon layer should be 20nm, and nothing layer in the range 40-60nm. Some questions: 1) which is the best agent to etch SiGe and preserve Si ? (I've found that PA:HF:H2O, 1:1:1 where PA=paracetic acid) should have a good selectivity, but did not found a numerical estimate. 2) is it possible to realize a so large SON structure or the thin silicon layer will surely destroy ? 3) which will be dislocation density in the thin silicon layer ? Best regards, Andrea