A backside illuminated (“BSI”) complementary metal-oxide semiconductor (“CMOS”) image sensor includes a photosensitive region disposed within a semiconductor layer and a stress adjusting layer. The photosensitive region is sensitive to light incident on a backside of the BSI CMOS image sensor to collect an image charge. The stress adjusting layer is disposed on a backside of the semiconductor layer to establish a stress characteristic that encourages photo-generated charge carriers to migrate towards the photosensitive region.