Canon S95 has a 10.0MP 1/1.7 (7.44 x 5.58 mm ) sized CCD sensor and features Digic 4 processor. On the other hand, Canon S110 has a 12.0MP 1/1.7" (7.44 x 5.58 mm ) sized CMOS sensor and features Digic 5 processor.
Below you can see the S95 and S110 sensor size comparison.
Canon S95 and Canon S110 have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Canon S95 has 20% larger pixel area compared to Canon S110, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Canon S95 and Canon S110 sensors have been tested by DxO and the results show that S110 has a better overall score of 48, 1 points higher compared to S95's score of 47.