@Uri Shaked: The nwell is not part of the device generator because even though I could draw one around an array of devices, it's not clear to me what the array is supposed to look like. Honestly, it probably shouldn't be a generated device at all because the layout of the core SONOS bit cell will ultimately be custom if you want to get any kind of density out of a bit array. For just playing around with the technology like you're doing, it's okay.