Stress Modulation for Dielectric Layers

A method comprising:

• forming a dummy gate stack on a semiconductor fin in a wafer, wherein the semiconductor fin protrudes higher than isolation regions on opposite sides of the semiconductor fin;
• etching the dummy gate stack to form an opening;
• and
• in a process chamber, filling the opening with a silicon nitride layer using Atomic Layer Deposition (ALD), wherein the ALD comprises a first plurality of ALD cycles, each comprising:
• introducing a silicon-containing precursor into the process chamber;
• purging the silicon-containing precursor from the process chamber;
• introducing hydrogen radicals into the process chamber;
• purging the hydrogen radicals from the process chamber;
• introducing a nitrogen-containing precursor into the process chamber;
• and
• purging the nitrogen-containing precursor from the process chamber.

A method comprising:

• etching a dummy gate stack to form an opening;
• forming a silicon nitride layer extending into the opening using Atomic Layer Deposition (ALD), wherein the forming the silicon nitride layer comprises forming a plurality of sub-layers;
• and
• performing a plurality of treatments on the silicon nitride layer using hydrogen radicals, wherein each of the plurality of treatments is performed after one of the plurality of sub-layers is formed.