Contact formation with reduced dopant loss and increased dimensions

A structure comprising:

• a semiconductor region;
• a gate stack over the semiconductor region;
• a gate spacer contacting the gate stack;
• a first source/drain region, wherein the first source/drain region comprises a dopant, and the dopant is of p-type or n-type;
• a dielectric layer over the first source/drain region;
• a first contact spacer in the dielectric layer;
• and
• a first contact plug encircled by the first contact spacer, wherein the first contact spacer and the first contact plug comprise the dopant therein.

A structure comprising:

• a first source/drain region and a second source/drain region;
• a contact etch stop layer comprising portions overlapping the first source/drain region and the second source/drain region;
• an inter-layer dielectric over the contact etch stop layer;
• a first contact plug in the inter-layer dielectric and the contact etch stop layer, wherein the first contact plug is over and electrically coupling to the first source/drain region;
• a first contact spacer encircling the first contact plug, wherein the first contact spacer comprises a dopant that is also comprised in the first source/drain region and the second source/drain region;
• a second contact plug in the inter-layer dielectric and the contact etch stop layer, wherein the second contact plug is over and electrically coupling to the second source/drain region;
• and
• a second contact spacer encircling the second contact plug, wherein a top portion of the second contact spacer is free from the dopant therein.