Method for making a trench isolation for semiconductor devices

A method of fabricating an integrated circuit having a plurality of active regions separated by field isolation regions, the method comprising:

• etching the substrate to form trenches separating the active regions from one another;
• partially filling each trench with a first dielectric material so that sidewalls of the trench are covered with the first dielectric;
• directing ions at an upper surface of the substrate after partially filling the trenches with the first dielectric material so that ions are implanted in regions of the substrate below the partially-filled trenches, such that substantially all of the ions implanted below the trenches are displaced horizontally from sidewall edges of the trenches;
• and
• substantially filling unfilled portions of the trenches with a second dielectric material after the ions are implanted in the substrate below the trenches.

A method of fabricating a device having a plurality of active regions separated by field isolation regions, the method comprising:

• forming impurity-doped regions in the active regions;
• forming isolation trenches in the substrate to separate the active regions from one another;
• partially filling each trench with a dielectric material so that at least sidewalls of the trench are coated with the dielectric;
• implanting ions in regions of the substrate below the trenches after partially filling the trenches with the dielectric material, such that substantially all of the ions implanted below the trenches are displaced horizontally from sidewall edges of the trenches;
• and
• substantially filling unfilled portions of the trenches with a dielectric material after the ions are implanted in the substrate below the trenches.