A first aspect of the invention provides for a transistor. The transistor may include a gate stack on a substrate; a channel under the gate stack within the substrate; a doped source and a doped drain on opposing sides of the channel, the doped source and the doped drain each including a dopant, wherein the dopant and the channel together have a first coefficient of diffusion and the doped source and the doped drain each have a second coefficient of diffusion; and a doped extension layer substantially separating each of the doped source and the doped drain from the channel, the doped extension layer having a third coefficient of diffusion, wherein the third coefficient of diffusion is greater than the first coefficient of diffusion.