Semiconductor device and method

A method comprising:

• forming a first fin and a second fin extending from a semiconductor substrate;
• forming a liner layer along a first sidewall of the first fin, a second sidewall of the second fin, and a top surface of the semiconductor substrate with an atomic layer deposition process, the liner layer formed of silicon oxynitride having a nitrogen concentration;
• forming a fill material on the liner layer with a flowable chemical vapor deposition process, the flowable chemical vapor deposition process comprising:
• depositing a semiconductor layer on the liner layer, the semiconductor layer formed of silicon;
• and
• annealing the semiconductor layer and the liner layer, the annealing converting the semiconductor layer and an upper portion of the liner layer to silicon oxide, the annealing decreasing the nitrogen concentration of a lower portion of the liner layer;
• and
• recessing the liner layer and the fill material to form an isolation region between the first fin and the second fin.

A method comprising:

• forming a first fin and a second fin extending from a semiconductor substrate;
• depositing a liner layer along a first sidewall of the first fin, a second sidewall of the second fin, and a top surface of the semiconductor substrate with an atomic layer deposition process;
• depositing a fill material on the liner layer with a flowable chemical vapor deposition process, the flowable chemical vapor deposition process comprising an anneal process, the anneal process decreasing an etching selectivity between the liner layer and the fill material relative an etching process;
• forming an isolation region between the first fin and the second fin by etching the liner layer and the fill material with the etching process;
• and
• forming a gate structure on a top surface of the isolation region, the first sidewall of the first fin, and the second sidewall of the second fin.