Semiconductor devices having source/drain regions with strain-inducing layers and methods of manufacturing such semiconductor devices

A semiconductor device, comprising;

• a substrate having a semiconductor fin structure protruding upwardly therefrom, the fin structure including a channel region;
• a gate structure on an upper surface of the channel region, the gate structure including a gate dielectric layer on the channel region, a gate electrode pattern on the gate dielectric layer and gate spacers on opposed sidewalls of the gate electrode pattern;
• a first source/drain region and a second source/drain region on opposite sides of the channel region, the first source/drain region including a first strain-inducing layer on a sidewall of the channel region and a second strain-inducing layer, wherein the first strain-inducing layer is between the second strain-inducing layer and the channel region,
• wherein the channel region has a first conductivity type and the first and second strain-inducing layers have a second conductivity type that is opposite the first conductivity type,
• wherein a concentration of second conductivity type dopants in the second strain-inducing layer is at least two orders of magnitude greater than a concentration of second conductivity type dopants in the first strain-inducing layer, and
• wherein a thickness of the first strain-inducing layer along an entirety of the sidewall of the channel region is substantially uniform.