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
This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for s...This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for some catalogs. One catalog features properties—including charge, mass, and angular momentum—of objects. Another catalog features all known and some possible elementary particles. Assumptions include that multipole-expansion mathematics has uses regarding long-range interactions, such as gravity, and that nature includes six isomers of all elementary particles other than long-range-interaction bosons. One isomer associates with ordinary matter. Five isomers are associated with dark matter. Multipole notions help explain large-scale aspects such as the rate of expansion of the universe.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
在自然条件下利用紫外灯补充紫外线B,模拟臭氧层破坏10%、20%后昆明地区增加的紫外线B强度2.5和5 k J/(m^2·d),研究了紫外线B增加对滇杨(Populus yunnanensis)(2 430 m)和川杨(P.szechuanica)(3 300 m)光合参数、暗呼吸速率、叶片...在自然条件下利用紫外灯补充紫外线B,模拟臭氧层破坏10%、20%后昆明地区增加的紫外线B强度2.5和5 k J/(m^2·d),研究了紫外线B增加对滇杨(Populus yunnanensis)(2 430 m)和川杨(P.szechuanica)(3 300 m)光合参数、暗呼吸速率、叶片厚度的影响。结果表明:与对照相比,2.5和5 k J/(m^2·d)紫外线B处理使滇杨的净光合速率(Pn)分别降低了32%和51%,川杨则降低了16%和39%;相反,2.5和5 k J/(m^2·d)紫外线B显著提高了暗呼吸速率(Rd)和叶片厚度;相关性分析表明:两种杨树的叶片净光合速率与水分利用效率均呈显著正相关,与暗呼吸速率呈显著的负相关(P<0.01)。此外,2.5 k J/(m^2·d)紫外线B强度对滇杨和川杨的气孔导度、暗呼吸速率及其与净光合效率比值的影响不同;且川杨的净光合速率、暗呼吸速率、叶片厚度都显著大于滇杨,这些差异反映出生长在高海拔环境下的川杨比生长在低海拔的滇杨对紫外线B增强具有更强的耐性。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)。
文摘This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for some catalogs. One catalog features properties—including charge, mass, and angular momentum—of objects. Another catalog features all known and some possible elementary particles. Assumptions include that multipole-expansion mathematics has uses regarding long-range interactions, such as gravity, and that nature includes six isomers of all elementary particles other than long-range-interaction bosons. One isomer associates with ordinary matter. Five isomers are associated with dark matter. Multipole notions help explain large-scale aspects such as the rate of expansion of the universe.
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.
文摘在自然条件下利用紫外灯补充紫外线B,模拟臭氧层破坏10%、20%后昆明地区增加的紫外线B强度2.5和5 k J/(m^2·d),研究了紫外线B增加对滇杨(Populus yunnanensis)(2 430 m)和川杨(P.szechuanica)(3 300 m)光合参数、暗呼吸速率、叶片厚度的影响。结果表明:与对照相比,2.5和5 k J/(m^2·d)紫外线B处理使滇杨的净光合速率(Pn)分别降低了32%和51%,川杨则降低了16%和39%;相反,2.5和5 k J/(m^2·d)紫外线B显著提高了暗呼吸速率(Rd)和叶片厚度;相关性分析表明:两种杨树的叶片净光合速率与水分利用效率均呈显著正相关,与暗呼吸速率呈显著的负相关(P<0.01)。此外,2.5 k J/(m^2·d)紫外线B强度对滇杨和川杨的气孔导度、暗呼吸速率及其与净光合效率比值的影响不同;且川杨的净光合速率、暗呼吸速率、叶片厚度都显著大于滇杨,这些差异反映出生长在高海拔环境下的川杨比生长在低海拔的滇杨对紫外线B增强具有更强的耐性。
