TCAD simulations of a novel UV and blue-extended photodiode

In this paper, a new UV and blue-extended photodiode with an octagon-ring-shaped structure is proposed, which have increased responsivity for the UV and blue light, high responsive speed with short rise and fall time and UV/blue selectivity. TCAD simulation approach is used to analyze the structural characteristics and photoelectric characteristics of this new photodiode. For the structural characteristics, doping profile, potential distribution and Electric field distribution are analyzed simply. For the photoelectric characteristics, the influences caused by doping concentration of n-well on dark current, avalanche breakdown voltage and transient response are discussed in detail. The finger distance (D) between two adjacent P+ anodes, the width (W) of P+ anode and the ratio of D/W are analyzed, witch affects the spectral response, DC characteristic and transient response obviously. The work of TCAD simulation in this paper is conducive to extract model parameters and process parameters of this new photodiode, which will further be used for numerical simulation to analyze its photoelectric characteristics, noise characteristics more accurately. This work is also a significant and helpful guide for device design and chip fabrication.