Semiconductor device and method

A method of forming a semiconductor device, the method comprising:

• forming a semiconductor fin protruding from a substrate;
• forming a gate stack over the semiconductor fin;
• forming a source/drain region on the semiconductor fin adjacent the gate stack;
• forming a first dielectric layer extending over the source/drain region and the gate stack;
• forming a second dielectric layer on the first dielectric layer, wherein the second dielectric layer is a different material than the first dielectric layer, wherein the second dielectric layer is formed having a first atomic percentage of nitrogen;
• forming an insulating layer on the second dielectric layer, wherein the insulating layer is a different material than the second dielectric layer;
• performing an annealing process, wherein the second dielectric layer has a second atomic percentage of nitrogen after performing the annealing process that is smaller than the first atomic percentage of nitrogen;
• and
• after performing the annealing process, forming a conductive feature extending through the insulating layer, the second dielectric layer, and the first dielectric layer to contact the source/drain region.

A device comprising:

• a fin extending from a semiconductor substrate;
• a gate stack over and along a sidewall of the fin;
• a gate spacer along a sidewall of the gate stack and a sidewall of the fin;
• an epitaxial source/drain region in the fin and adjacent the gate stack;
• a silicon nitride layer extending over the epitaxial source/drain region and the gate spacer;
• a silicon oxynitride layer on the silicon nitride layer;
• an insulating layer on the silicon oxynitride layer;
• and
• a contact extending through the insulating layer, the silicon oxynitride layer, and the silicon nitride layer to the epitaxial source/drain region.