Patent attributes
Undesirable transistor leakage in transistor structures becomes greatly reduced in substrates having a doped implant region formed via pulling back first and second layers of a process stack. A portion of the substrate, which also has first and second layers deposited thereon, defines the process stack. The dopant is selected having the same n- or p-typing as the substrate. Through etching, the first and second layers of the process stack become pulled back from a trench wall of the substrate to form the implant region. Occupation of the implant region by the dopant prevents undesirable transistor leakage because the electrical characteristics of the implant region are so significantly changed, in comparison to central areas of the substrate underneath the first layer, that the threshold voltage of the implant region is raised to be about equivalent to or greater than the substantially uniform threshold voltage in the central area.
