A method that includes providing a semiconductor substrate having a mask on a
surface
thereof. The mask includes a first region having no masking elements and a second
region having a plurality of masking elements. Each of the plurality of masking
elements has a dimension that is equal to a first length, the first length less
than twice a diffusion length of a dopant. The method further includes bombarding
the semiconductor substrate and masking element with ions of the dopant. The ions
form a first impurity concentration in the first region and a second impurity concentration
in the second region.
