In general, the present invention discloses at least one trench isolation region formed in a semiconductor substrate to electrically and/or optically isolate at least one active region from another active region. The at least one trench isolation region comprises a bottom portion and first and second trench sidewalls. At least one trench sidewall is adjacent a doped region. The at least one sidewall adjacent a doped region has a higher impurity dopant concentration than impurity doped regions surrounding the at least one trench isolation region.