Numerical simulation of the effect of gold doping on the resistance to neutron irradiation of silicon diodes

We have carried out a numerical simulation of the effect of gold doping on the electrical characteristics of long silicon diodes exposed to neutron irradiation. The aim is to investigate the effect of gold on the hardness of the irradiated diodes. The reverse current voltage and capacitance voltage characteristics of doped and undoped diodes are calculated for different irradiation doses. The leakage current and the effective doping density are extracted from these two characteristics respectively. The hardness of the diodes is evaluated from the evolution of the leakage current and the effective doping density with irradiation doses. It was found that diodes doped with gold are less sensitive to irradiation than undoped ones. Thus gold appears to stabilise the electrical properties on irradiation. The conduction mechanism is studied by the evolution of the current with temperature. The evaluated activation energy indicates that as the gold doping or irradiation dose increases, the current switches from the basic diffusion to the generation-recombination process, and that it can even become ohmic for very high gold densities or irradiation doses.

Total dose test with γ-ray for silicon single photon avalanche diodes

Gamma-ray(γ-ray)radiation for silicon single photon avalanche diodes(Si SPADs)is evaluated,with total dose of 100 krad(Si)and dose rate of 50 rad(Si)/s by using 60Co as theγ-ray radiation source.The breakdown voltage,photocurrent,and gain have no obvious change after the radiation.However,both the leakage current and dark count rate increase by about one order of magnitude above the values before the radiation.Temperature-dependent current-voltage measurement results indicate that the traps caused by radiation function as generation and recombination centers.Both leakage current and dark count rate can be almost recovered after annealing at 200℃for about 2 hours,which verifies the radiation damage mechanics.

Highly efficient silicon light emitting diodes produced by doping engineering

This paper reviews our recent progress on silicon （Si） pn junction light emitting diodes with locally doping engineered carrier potentials. Boron implanted Si diodes with dislocation loops have electroluminescence （EL） quantum efficiency up to 0.12%, which is two orders of magnitude higher than those without dislocations. Boron gettering along the strained dislocation lines produces locally p-type spike doping at the dislocations, which have potential wells for bounding spatially indirect excitons. Thermal dissociation of the bound excitons releases free carriers, leading to an anomalous increase of the band to band luminescence with increasing tempera- ture. Si light emitting diodes with external quantum efficiency of 0.2% have been also demonstrated by implementation of pnpn modulation doping arrays.

Dual-polarization wavelength conversion of 16-QAM signals in a single silicon waveguide with a lateral p-i-n diode[Invited]

A polarization-diversity loop with a silicon waveguide with a lateral p-i-n diode as a nonlinear medium is used to realize polarization insensitive four-wave mixing. Wavelength conversion of seven dual-polarization 16-quadrature amplitude modulation(QAM) signals at 16 GBd is demonstrated with an optical signal-to-noise ratio penalty below 0.7 dB. High-quality converted signals are generated thanks to the low polarization dependence(≤0.5 dB) and the high conversion efficiency(CE) achievable. The strong Kerr nonlinearity in silicon and the decrease of detrimental free-carrier absorption due to the reverse-biased p-i-n diode are key in ensuring high CE levels.

High-voltage 4H-SiC PiN diodes with the etched implant junction termination extension

This paper presents the design and fabrication of an etched implant junction termination extension（JTE）for high-voltage 4H-SiC PiN diodes. Unlike the conventional JTE structure, the proposed structure utilizes multiple etching steps to achieve the optimum JTE concentration range. The simulation results show that the etched implant JTE method can improve the blocking voltage of SiC PiN diodes and also provides broad process latitude for parameter variations, such as implantation dose and activation annealing condition. The fabricated SiC PiN diodes with the etched implant JTE exhibit a highest blocking voltage of 4.5 kV and the forward on-state voltage of 4.6 V at room temperature. These results are of interest for understanding the etched implant method in the fabrication of high-voltage power devices.

A SKIROC2-based prototype electronics system for silicon PIN array

Background Silicon PIN(Si-PIN)diode has been widely used in high-energy physics experiments.The next-generation experiments ask for a large amount of the Si-PIN diode arrays,leading to a requirement for the electronics system with features of higher integration and lower power consumption than the traditional ones.Purpose The aim was to design and implement a prototype of multi-channel electronic system,which is based on the SKIROC2 ASIC.The system is also considered as the pre-research of the silicon–tungsten(Si-W)ECAL for CEPC.Methods The prototype is divided into two parts,so that it has the potentiality for the expansion of more readout channels.The front-end board(FEB),which carries a Si-PIN diode array and an ASIC of SKIROC2 on it,provides high voltage to the Si-PIN diodes and processes the signals as well.The FEB is configured by a data interface board(DIF)and sends data to the DIF,which then transfers data to PC via USB interface after packing process.Results The prototype electronics system has been implemented.The equivalent noise level of all the 64 channels is below 0.4 fC.The dynamic range is up to+3000 fC with an integral nonlinearity(INL)of 0.2%,and the gain non-uniformity is better than 5%.The energy resolution with 59 keV X-rays from 241Am is about 13.3%(in RMS),while the signal-to-noise ratio(SNR)reaches about 10.9 for minimum ionizing particles(MIPs).Conclusion In this paper,a SKIROC2-based prototype electronics system for Si-PIN array,as well as the performance test,has been presented.The system has features of high integration,low noise,and high dynamic range.The SKIROC2,as well as the design concept of the electronics system,can be applied to the preliminary prototype Si-W ECAL of CEPC.