Semiconductor devices and methods of manufacture thereof

摘要

A first gate dielectric of a first transistor is disposed over a workpiece in a first region, and a second gate dielectric of a second transistor is disposed over the workpiece in a second region. The second gate dielectric comprises a different material than the first gate dielectric. A first dopant-bearing metal comprising a first dopant is disposed in recessed regions of the workpiece proximate the first gate dielectric, and a second dopant-bearing metal comprising a second dopant is disposed in recessed regions of the workpiece proximate the second gate dielectric. A first doped region comprising the first dopant is disposed in the workpiece adjacent the first dopant-bearing metal. A second doped region comprising the second dopant is disposed in the workpiece adjacent the second dopant-bearing metal. The dopant-bearing metals and the doped regions comprise source and drain regions of the first and second transistors.