Gate-all-around (GAA) transistors with shallow source/drain regions and methods of fabricating the same provide a GAA transistor that includes one or more channels positioned between a source region and a drain region. The one or more channels, which may be nanowire, nanosheet, or nanoslab semiconductors, are surrounded along a longitudinal axis by gate material. At a first end of the channel is a source region and at an opposite end of the channel is a drain region. To reduce parasitic capacitance between a bottom gate and the source and drain regions, a filler material is provided adjacent the bottom gate, and the source and drain regions are grown on top of the filler material. In this fashion, the bottom gate does not abut the source region or the drain region, reducing geometries which would contribute to parasitic capacitance.