基于4H-SiC APD单光子探测的主动淬灭电路研究

Research on active quenching circuit based on single-photon detection of 4 H-SiC APD

为了对比不同类型淬灭电路对4H-SiC雪崩光电二极管(APD)探测性能的影响,采用被动淬灭电路(PQC)和主动淬灭电路(AQC),对两种类型SiC紫外APD进行了单光子探测实验,发现在PQC较长死区时间内,会频发后脉冲现象,导致APD的暗计数率(DCR)较高,从而降低器件的信噪比;对APD后脉冲概率的时间分布进行了研究,并进一步对AQC在更高器件过偏压下单光子探测中出现的问题进行了分析,提出了电路改进方案。结果表明,通过将AQC死区时间调整至45 ns,在相同单光子探测效率下,可将器件DCR减少至原先水平的1/4;通过有效抑制后脉冲和加快APD恢复速度,AQC可使器件展现出更加优越的探测性能。此研究为SiC APD在单光子探测中的应用提供了一定的参考。

In order to compare the effects of different types of quenching circuits on the detection performance of 4H-SiC avalanche photodiodes(APD),single-photon detection experiments were conducted on two types of SiC ultraviolet APD by using passive quenching circuits(PQC)and active quenching circuits(AQC).It was found that during a long dead time in PQC,post pulse phenomena occur frequently,resulting in a higher dark counting rate(DCR)of APD,thereby reducing the signal-to-noise ratio of the device.A study was conducted on the time distribution of pulse probability after APD,and further analysis was conducted on the problems encountered by AQC in single-photon detection under higher device bias.A circuit improvement plan was proposed.The research results indicate that by adjusting the dead time of AQC to 45 ns,the device DCR can be reduced to 1/4 of the original level under the same single-photon detection efficiency.By effectively suppressing post pulse and accelerating APD recovery speed,AQC can enable the device to exhibit superior detection performance.This study provides a certain reference for the application of SiC APD in single-photon detection.