Methods for doping a sub-fin region of a semiconductor fin structure and devices containing the same

Methods for doping a subfin region of a semiconductor fin structure include forming a fin on a substrate; forming an oxide material on the substrate and a portion of the fin that corresponds to a sub-fin region of the fin; forming a hard mask on a top-fin region of the fin that is disposed above the sub-fin region; exposing a surface of the sub-fin region by removing the oxide material from a surface of the sub-fin region and leaving a layer of the oxide material on the substrate; depositing a dopant material on the hard mask, the surface of the subfin region, and the layer of the oxide material on the substrate; and removing the hard mask from the top-fin region to expose a surface of the top-fin region. Devices constructed using the disclosed methods are also provided, and other embodiments are discussed.