摘要 |
Source and drain regions are formed in first regions of low concentration formed on a surface of a semiconductor surface, and a second region with doping concentration higher than that of the first regions is formed around the first regions. Further in the second region, third regions with doping concentration higher than that of the second region are formed separate from each other. By virtue of this, a rise of the threshold voltage attendant on a decrease of the channel length is canceled out by the third regions and the short channel effect is suppressed. Further, since doping concentration of the first region is low, high carrier mobility can be obtained.
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