Manufacture of FET transistor with elevated source and drain regions and minimal channel length, overlaps regions of differing dopant levels at each end of gate

摘要

A gate structure is constructed on the substrate. Near one end of this, a region is doped to a first concentration. A second doped region is formed at a second concentration, overlapping the first. Yet a third doped region is formed, overlapping the second, and having a third doping level differing from the others. The raised drain includes the third region. The second dopant concentration is lower than the third.