Semiconductor device and method of manufacturing the same

A semiconductor device, comprising:

• a substrate;
• a source/drain region within the substrate;
• a well region abutting the source/drain region;
• a first stressor layer covering the well region;
• a second stressor layer disposed on the first stressor layer;
• a buffer layer disposed between the first stressor layer and the second stressor layer;
• an interlayer dielectric disposed on the second stressor layer ;
• and
• a first contact penetrating the interlayer dielectric, the second stressor layer, and the buffer layer,
• wherein the first contact has a first lateral surface and a second lateral surface nonparallel to the first lateral surface, and wherein the first lateral surface abuts the interlayer dielectric, and the second lateral surface abuts the buffer layer.

A semiconductor device, comprising:

• a substrate;
• a gate structure disposed on the substrate;
• a source/drain region within the substrate and having a first conductive type;
• a well region abutting the source/drain region and having the first conductive type;
• a first stressor layer covering the well region, wherein the first stressor layer is configured to apply a first stress to the substrate;
• a second stressor layer disposed on the first stressor layer, wherein the second stressor layer is configured to apply a second stress to the substrate, and the first stress is opposite to the second stress;
• a buffer layer disposed between the first stressor layer and the second stressor layer;
• a first contact penetrating the second stressor layer and the buffer layer,
• wherein the first contact is spaced apart from the first stressor layer by the buffer layer.