Electrostatic discharge (ESD) structures are provided. An ESD structure includes a semiconductor substrate, a first epitaxy region with a first type of conductivity over the semiconductor substrate, a second epitaxy region with a second type of conductivity over the semiconductor substrate, and a plurality of first semiconductor layers and a plurality of second semiconductor layers. The first and second semiconductor layers are alternatingly stacked over the semiconductor substrate and between the first and second epitaxy regions. A first conductive feature is formed over the first epitaxy region and outside an oxide diffusion region. A second conductive feature is formed over the second epitaxy region and outside the oxide diffusion region. The oxide diffusion region is disposed between the first and second conductive features.