This paper proposes two optimal designs of single photon avalanche diodes(SPADs) minimizing dark count rate(DCR). The first structure is introduced as p^+/pwell/nwell, in which a specific shallow pwell layer is added ...This paper proposes two optimal designs of single photon avalanche diodes(SPADs) minimizing dark count rate(DCR). The first structure is introduced as p^+/pwell/nwell, in which a specific shallow pwell layer is added between p^+and nwell layers to decrease the electric field below a certain threshold. The simulation results show on average 19.7%and 8.5% reduction of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. Moreover, a new structure is introduced as n+/nwell/pwell, in which a specific shallow nwell layer is added between n+and pwell layers to lower the electric field below a certain threshold. The simulation results show on average 29.2% and 5.5% decrement of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. It is shown that in higher excess biases(about 6 volts), the n+/nwell/pwell structure is proper to be integrated as digital silicon photomultiplier(dSiPM) due to low DCR. On the other hand, the p^+/pwell/nwell structure is appropriate to be utilized in dSiPM in high temperatures(above 50?C) due to lower DCR value.展开更多
The influence of the virtual guard ring width(GRW)on the performance of the p-well/deep n-well single-photon avalanche diode(SPAD)in a 180 nm standard CMOS process was investigated.TCAD simulation demonstrates that th...The influence of the virtual guard ring width(GRW)on the performance of the p-well/deep n-well single-photon avalanche diode(SPAD)in a 180 nm standard CMOS process was investigated.TCAD simulation demonstrates that the electric field strength and current density in the guard ring are obviously enhanced when GRW is decreased to 1μm.It is experimentally found that,compared with an SPAD with GRW=2μm,the dark count rate(DCR)and afterpulsing probability(AP)of the SPAD with GRW=1μm is significantly increased by 2.7 times and twofold,respectively,meanwhile,its photon detection probability(PDP)is saturated and hard to be promoted at over 2 V excess bias voltage.Although the fill factor(FF)can be enlarged by reducing GRW,the dark noise of devices is negatively affected due to the enhanced trap-assisted tunneling(TAT)effect in the 1μm guard ring region.By comparison,the SPAD with GRW=2μm can achieve a better trade-off between the FF and noise performance.Our study provides a design guideline for guard rings to realize a low-noise SPAD for large-array applications.展开更多
针对现有单光子探测器模块价格昂贵和体积大的不足,设计了基于In Ga As/In P雪崩光电二极管(APD)的便携式单光子探测器,给出了探测器温控模块和偏置电压源的设计电路,门控信号的产生和雪崩信号的提取由FPGA完成。实验结果表明:在200 MH...针对现有单光子探测器模块价格昂贵和体积大的不足,设计了基于In Ga As/In P雪崩光电二极管(APD)的便携式单光子探测器,给出了探测器温控模块和偏置电压源的设计电路,门控信号的产生和雪崩信号的提取由FPGA完成。实验结果表明:在200 MHz门控条件且制冷温度为-55℃时,探测器的最大光子探测效率(PDE)约为16%,当探测效率为12%时,暗计数率(DCR)约为8.2×10-6/ns。展开更多
Planar semiconductor InGaAs/InP single photon avalanche diodes with high responsivity and low dark count rate are preferred single photon detectors in near-infrared communication.However,even with well-designed struct...Planar semiconductor InGaAs/InP single photon avalanche diodes with high responsivity and low dark count rate are preferred single photon detectors in near-infrared communication.However,even with well-designed structures and well-con-trolled operational conditions,the performance of InGaAs/InP SPADs is limited by the inherent characteristics of avalanche pro-cess and the growth quality of InGaAs/InP materials.It is difficult to ensure high detection efficiency while the dark count rate is controlled within a certain range at present.In this paper,we fabricated a device with a thick InGaAs absorption region and an anti-reflection layer.The quantum efficiency of this device reaches 83.2%.We characterized the single-photon performance of the device by a quenching circuit consisting of parallel-balanced InGaAs/InP single photon detectors and single-period sinus-oidal pulse gating.The spike pulse caused by the capacitance effect of the device is eliminated by using the characteristics of parallel balanced common mode signal elimination,and the detection of small avalanche pulse amplitude signal is realized.The maximum detection efficiency is 55.4%with a dark count rate of 43.8 kHz and a noise equivalent power of 6.96×10^(−17 )W/Hz^(1/2) at 247 K.Compared with other reported detectors,this SPAD exhibits higher SPDE and lower noise-equivalent power at a higher cooling temperature.展开更多
High detection efficiency and low intrinsic dark count rate are two advantages of superconducting nanowire single photon detectors(SNSPDs).However,the stray photons penetrated into the fiber would cause the extrinsic ...High detection efficiency and low intrinsic dark count rate are two advantages of superconducting nanowire single photon detectors(SNSPDs).However,the stray photons penetrated into the fiber would cause the extrinsic dark count rate,owing to the free running mode of SNSPDs.In order to improve the performance of SNSPDs in realistic scenarios,stray photons should be investigated and suppression methods should be adopted.In this study,we demonstrate the pulsegated mode,with 500 kHz gating frequency,of a commercial SNSPD system for suppressing the response of stray photons about three orders of magnitude than its free-running counterpart on the extreme test conditions.When we push the gating frequency to 8 MHz,the dark count rate still keeps under 4% of free-running mode.In experiments,the intrinsic dark count rate is also suppressed to 4.56 × 10^(-2) counts per second with system detection efficiency of 76.4372%.Furthermore,the time-correlated single-photon counting analysis also approves the validity of our mode in suppressing the responses of stray photons.展开更多
文摘This paper proposes two optimal designs of single photon avalanche diodes(SPADs) minimizing dark count rate(DCR). The first structure is introduced as p^+/pwell/nwell, in which a specific shallow pwell layer is added between p^+and nwell layers to decrease the electric field below a certain threshold. The simulation results show on average 19.7%and 8.5% reduction of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. Moreover, a new structure is introduced as n+/nwell/pwell, in which a specific shallow nwell layer is added between n+and pwell layers to lower the electric field below a certain threshold. The simulation results show on average 29.2% and 5.5% decrement of p^+/nwell structure’s DCR comparing with similar previous structures in different operational excess bias and temperatures respectively. It is shown that in higher excess biases(about 6 volts), the n+/nwell/pwell structure is proper to be integrated as digital silicon photomultiplier(dSiPM) due to low DCR. On the other hand, the p^+/pwell/nwell structure is appropriate to be utilized in dSiPM in high temperatures(above 50?C) due to lower DCR value.
基金Supported by the National Natural Science Foundation of China(NSFC)(62174166,11991063,U2241219)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01,22JC1402902)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB43010200)。
基金supported by the Jiangsu Agricultural Science and Technology Innovation Fund of China(No.CX(21)3062)the National Natural Science Foundation of China(No.62171233).
文摘The influence of the virtual guard ring width(GRW)on the performance of the p-well/deep n-well single-photon avalanche diode(SPAD)in a 180 nm standard CMOS process was investigated.TCAD simulation demonstrates that the electric field strength and current density in the guard ring are obviously enhanced when GRW is decreased to 1μm.It is experimentally found that,compared with an SPAD with GRW=2μm,the dark count rate(DCR)and afterpulsing probability(AP)of the SPAD with GRW=1μm is significantly increased by 2.7 times and twofold,respectively,meanwhile,its photon detection probability(PDP)is saturated and hard to be promoted at over 2 V excess bias voltage.Although the fill factor(FF)can be enlarged by reducing GRW,the dark noise of devices is negatively affected due to the enhanced trap-assisted tunneling(TAT)effect in the 1μm guard ring region.By comparison,the SPAD with GRW=2μm can achieve a better trade-off between the FF and noise performance.Our study provides a design guideline for guard rings to realize a low-noise SPAD for large-array applications.
文摘针对现有单光子探测器模块价格昂贵和体积大的不足,设计了基于In Ga As/In P雪崩光电二极管(APD)的便携式单光子探测器,给出了探测器温控模块和偏置电压源的设计电路,门控信号的产生和雪崩信号的提取由FPGA完成。实验结果表明:在200 MHz门控条件且制冷温度为-55℃时,探测器的最大光子探测效率(PDE)约为16%,当探测效率为12%时,暗计数率(DCR)约为8.2×10-6/ns。
基金jointly supported by the National Key Research and Development Program of China (2019YFB22-05202)National Natural Science Foundation of China(61774152)
文摘Planar semiconductor InGaAs/InP single photon avalanche diodes with high responsivity and low dark count rate are preferred single photon detectors in near-infrared communication.However,even with well-designed structures and well-con-trolled operational conditions,the performance of InGaAs/InP SPADs is limited by the inherent characteristics of avalanche pro-cess and the growth quality of InGaAs/InP materials.It is difficult to ensure high detection efficiency while the dark count rate is controlled within a certain range at present.In this paper,we fabricated a device with a thick InGaAs absorption region and an anti-reflection layer.The quantum efficiency of this device reaches 83.2%.We characterized the single-photon performance of the device by a quenching circuit consisting of parallel-balanced InGaAs/InP single photon detectors and single-period sinus-oidal pulse gating.The spike pulse caused by the capacitance effect of the device is eliminated by using the characteristics of parallel balanced common mode signal elimination,and the detection of small avalanche pulse amplitude signal is realized.The maximum detection efficiency is 55.4%with a dark count rate of 43.8 kHz and a noise equivalent power of 6.96×10^(−17 )W/Hz^(1/2) at 247 K.Compared with other reported detectors,this SPAD exhibits higher SPDE and lower noise-equivalent power at a higher cooling temperature.
基金Project supported by the National Natural Science Foundation of China(Grant No.61605248)the National Basic Research Program of China(Grant No.2013CB338002)。
文摘High detection efficiency and low intrinsic dark count rate are two advantages of superconducting nanowire single photon detectors(SNSPDs).However,the stray photons penetrated into the fiber would cause the extrinsic dark count rate,owing to the free running mode of SNSPDs.In order to improve the performance of SNSPDs in realistic scenarios,stray photons should be investigated and suppression methods should be adopted.In this study,we demonstrate the pulsegated mode,with 500 kHz gating frequency,of a commercial SNSPD system for suppressing the response of stray photons about three orders of magnitude than its free-running counterpart on the extreme test conditions.When we push the gating frequency to 8 MHz,the dark count rate still keeps under 4% of free-running mode.In experiments,the intrinsic dark count rate is also suppressed to 4.56 × 10^(-2) counts per second with system detection efficiency of 76.4372%.Furthermore,the time-correlated single-photon counting analysis also approves the validity of our mode in suppressing the responses of stray photons.
