Techniques for fabricating nanowire-based devices are provided. In one aspect, a method for fabricating a semiconductor device is provided comprising the following steps. A wafer is provided having a silicon-on-insulator (SOI) layer over a buried oxide (BOX) layer. Nanowires and pads are etched into the SOI layer to form a ladder-like structure wherein the pads are attached at opposite ends of the nanowires. The BOX layer is undercut beneath the nanowires. The nanowires and pads are contacted with an oxidizing gas to oxidize the silicon in the nanowires and pads under conditions that produce a ratio of a silicon consumption rate by oxidation on the nanowires to a silicon consumption rate by oxidation on the pads of from about 0.75 to about 1.25. An aspect ratio of width to thickness among all of the nanowires may be unified prior to contacting the nanowires and pads with the oxidizing gas.