A method of forming a transistor device includes implanting a diffusion inhibiting species in a semiconductor-on-insulator substrate comprising a bulk substrate, a buried insulator layer, and a semiconductor-on-insulator layer, the semiconductor-on-insulator substrate having one or more gate structures formed thereon such that the diffusion inhibiting species is disposed in portions of the semiconductor-on-insulator layer corresponding to a channel region, and disposed in portions of the buried insulator layer corresponding to source and drain regions. A transistor dopant species is introduced in the source and drain regions. An anneal is performed so as to diffuse the transistor dopant species in a substantially vertical direction while substantially preventing lateral diffusion of the transistor dopant species into the channel region.