A system and method for fabricating non-planar devices while managing semiconductor processing yield and cost are described. A semiconductor device fabrication process forms a stack of alternating semiconductor layers. A trench is etched and filled with at least an oxide layer with a length at least that of a device channel length while being bounded by sites for a source region and a drain region. The process places a second silicon substrate on top of both the oxide layer in the trench and the top-most semiconducting layer of the stack. The two surfaces making contact by wafer bonding use the same type of semiconducting layer. The device is flipped such that the first substrate and the stack are on top of the second substrate. The process forms nanowires of a gate region from the stack in the top first substrate.