Shallow trench isolation (STI) with trench liner of increased thickness

摘要

Improved shallow trench isolation (STI) techniques are provided for semiconductor devices. For example, in accordance with an embodiment of the present invention, an integrated circuit includes a substrate, a first trench in the substrate, and a second trench in the substrate. A first silicon dioxide liner substantially lines the first trench. A second silicon dioxide liner substantially lines the second trench, wherein the second silicon dioxide liner has a thickness greater than a thickness of the first silicon dioxide liner. A silicon nitride liner is on the first silicon dioxide liner in the first trench but not on the second silicon dioxide liner in the second trench. A dielectric material fills the first and second trenches.