高光电探测效率CMOS单光子雪崩二极管器件

基于0.18μm CMOS工艺技术,制作了单光子雪崩二极管,可对650~950nm波段的微弱光进行有效探测.该器件采用P~+/N阱结构,P~+层深度较深,以提高对长光波的光子探测效率与响应度;采用低掺杂深N阱增大耗尽层厚度,可以提高探测灵敏度;深N阱与衬底形成的PN结可有效隔离衬底,降低衬底噪声;采用P阱保护环结构以预防过早边缘击穿现象.通过理论分析确定器件的基本结构参数及工艺参数,并对器件性能进行优化设计.实验结果表明,单光子雪崩二极管的窗口直径为10μm,器件的反向击穿电压为18.4V左右.用光强为0.001 W/cm~2的光照射,650nm处达到0.495A/W的响应度峰值;在2V的过偏压下,650~950nm波段范围内光子探测效率均高于30%,随着反向偏压的适当增大,探测效率有所提升.

The Research of High Photon Detection Efficiency CMOS Single Photon Avalanche Diode

A single photon avalanche diode designed with 0.18um CMOS technology is proposed,with which the weak light in 650~950nm wavelength can effectively detected.The single photon avalanche diode employs a P+/N-well structure,the deeper P+ layer is designed to improve the photon detection efficiency and responsivity in longer light wave;moreover,the increase of the thickness of depletion layer can be got with the use of the low doped deep N well,which can improve the detection sensitivity,and the PN junction formed by deep N well and substrate can effectively isolate substrate in order to reduce substrate noise.The use of P-well as the protection ring can prevent premature edge breakdown phenomenon.The basic structural parameters and process parameters of single photon avalanche diode devices are determined by theoretical analysis,and the device performance is optimized with Silvaco TCAD software.The simulation results show that when the optical window diameter of the device is 10 μm,the avalanche breakdown voltage is 18.4 V,with the illumination of 0.001 W/cm2,the peak of response is of 0.495 A/W at 650 nm will be got.when the reverse bias is excessed the breakdown voltage for 2 V,in the range of 650~950 nm wavelength,the photon detection efficiency is higher than 30%.With the increase of reverse bias,the detection efficiency is improved.