Si image sensors with wide spectral response and high robustness to ultraviolet light exposure

Si image sensors with a wide spectral response range and a high robustness to ultraviolet light exposure based on flattened Si surface are described in this paper. A photodiode (PD) fabrication technology is developed to form a thin surface high concentration layer with steep dopant profile on flattened Si surface. Due to this, PDs with a wide spectral response ranging from 200 to 1000 nm is achieved with almost 100% internal quantum efficiency to ultraviolet light (UV-light) waveband. In addition, high robustness of light sensitivity and dark current toward UV-light exposure is obtained. The developed technology is applied to in-pixel buried PDs of photodiode arrays and a CMOS image sensor. The advanced performances of fabricated sensors are verified with experimental results.