Semiconductor device

A structure of a semiconductor device comprising:

• a fin structure on a substrate;
• an isolation structure on the substrate;
• and
• a liner layer in contact with the fin structure and the isolation structure, wherein a first portion of the liner layer in contact with a sidewall of the fin structure has a nitrogen concentration different from a second portion of the liner layer in contact with a bottom surface of the isolation structure.

A structure of a semiconductor device comprising:

• a fin structure on a substrate;
• a liner layer lining a sidewall of the fin structure and a surface of the substrate, wherein the liner layer comprises silicon oxynitride and a nitrogen concentration of the liner layer increases as the liner layer extends downwardly;
• and
• an isolation structure in contact with the liner layer.