SEMICONDUCTOR STRUCTURE WITH MULTIPLE TRANSISTORS HAVING VARIOUS THRESHOLD VOLTAGES AND METHOD OF FABRICATION THEREOF

摘要

A seinxconauctor structure includes first, second, and third transistor elements each having a first screening region concurrently formed therein..A second screening region is formed in the second and third transistor elements such that there is at. least one characteristic of the screening region in the second transistor element that is different than the second screening region in the third transistor element. Different characteristics include doping concentration and depth of implant. In addition, a different characteristic may be achieved by concurrently implanting the second screening region in the second and third transistor element followed by implanting an additional dopant into the second screening region of the third transistor element