TRANSISTOR HAVING IMPURITY DENSITY DISTRIBUTION CAPABLE OF IMPROVING SHORT- CHANNEL EFFECT

摘要

The impurity concentration in the channel region of the MOS transistor has an impurity concentration profile having a shape such as a first-order function or higher higher order function or a Gaussian distribution with respect to the depth direction. Thus, the impurity concentration at the surface depletion layer end is set higher than the impurity concentration on the surface of the semiconductor substrate, or the impurity concentration distribution is set such that the impurity concentration slope in the channel region has a positive slope at the end of the surface depletion layer. do.