A semiconductor device may include a substrate and a hyper-abrupt junction region carried by the substrate. The hyper-abrupt region may include a first semiconductor layer having a first conductivity type, a first superlattice layer on the first semiconductor layer, a second semiconductor layer on the first superlattice layer and having a second conductivity type different than the first conductivity type, and a second superlattice layer on the second semiconductor layer. The semiconductor device may further include a gate dielectric layer on the second superlattice layer of the hyper-abrupt junction region, a gate electrode on the gate dielectric layer, and spaced apart source and drain regions adjacent the hyper-abrupt junction region.