基于180 nm标准CMOS工艺, 设计了一种能够有效提高光子探测效率的双电荷层结构的单光子雪崩二极管.该器件结构采用P电荷层和逆行掺杂的深N阱形成PN结, 选取不同的P电荷层掺杂浓度, 对击穿电压进行优化, 当P电荷层浓度为1×1018cm－3时, 击穿电压为17.8 Ｖ, 电场强度为5.26×105 V/cm.进一步研究发现N电荷层的位置会影响漂移电流密度和扩散电流密度.当在深N阱与N隔离层交界处掺杂形成N电荷层, 即N电荷层掺杂峰值距离器件表面为2.5 μm时, 器件性能最优.通过Silvaco TCAD仿真分析得到：在过偏压1 V下, 波长500 nm处的探测效率峰值为62%, 同时在300~700 nm范围内的光子探测效率均大于30%.

A single-photon avalanche diode with double charge layers is designed with 180 nm standard CMOS technology, which is able to improve photon detection efficiency. PN junction is formed by deep N-well with retrograde doping P-charge layer. The different doping concentration of P-charge layers are selected to optimize the breakdown voltage. When the P-charge layer concentration is 1×1018cm－3, the simulation results show that the breakdown voltage is 17.8 V and the electric field intensity is 5.26×105V/cm. Further study shows that the position of N-charge layer affects drift current density and diffusion current density. The device performance is optimal when the N-charge layer is doped at the contact of the deep N-well and the N isolation layer, in other words, when the peak of the N-charge layer is 2.5 μm from the surface of the device. By using Silvaco TCAD simulation analysis, which can get a conclusion that at a wavelength of 500 nm, the detection efficiency peak is 62% under bias voltage of 1 V, while the photon detection efficiency in the range of 300 nm to 700 nm is greater than 30%.