BACKGROUND

In recent years, the semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation.

Photo sensing devices are used to sense radiation such as light. These devices often use arrays of pixels or photodiodes to absorb radiation projected thereto and convert the sensed radiation into electrical signals. As a part of evolution, the size of photo sensing device can be reduced. However, issues related to dark current are more and more difficult to deal with, and furthermore, as the pixel sizes decrease, the amount of photons received by the photo sensing device decreases. As a result, the effect of dark current becomes more pronounced. Therefore, minimizing dark current is a critical issue for advanced technology. Furthermore, photo sensing device often suffers dopant diffusion issues, wherein the speed of detection of the photo sensing device may be reduced due to undesired diffusion.

