BACKGROUND Acetabular component positioning in total hip arthroplasty(THA)is of key importance to ensure satisfactory post-operative outcomes and to minimize the risk of complications.The majority of acetabular compon...BACKGROUND Acetabular component positioning in total hip arthroplasty(THA)is of key importance to ensure satisfactory post-operative outcomes and to minimize the risk of complications.The majority of acetabular components are aligned freehand,without the use of navigation methods.Patient specific instruments(PSI)and three-dimensional(3D)printing of THA placement guides are increasingly used in primary THA to ensure optimal positioning.AIM To summarize the literature on 3D printing in THA and how they improve acetabular component alignment.METHODS PubMed was used to identify and access scientific studies reporting on different 3D printing methods used in THA.Eight studies with 236 hips in 228 patients were included.The studies could be divided into two main categories;3D printed models and 3D printed guides.RESULTS 3D printing in THA helped improve preoperative cup size planning and post-operative Harris hip scores between intervention and control groups(P=0.019,P=0.009).Otherwise,outcome measures were heterogeneous and thus difficult to compare.The overarching consensus between the studies is that the use of 3D guidance tools can assist in improving THA cup positioning and reduce the need for revision THA and the associated costs.CONCLUSION The implementation of 3D printing and PSI for primary THA can significantly improve the positioning accuracy of the acetabular cup component and reduce the number of complications caused by malpositioning.展开更多
Simulating the total ionizing dose(TID)of an electrical system using transistor-level models can be difficult and expensive,particularly for digital-integrated circuits(ICs).In this study,a method for modeling TID eff...Simulating the total ionizing dose(TID)of an electrical system using transistor-level models can be difficult and expensive,particularly for digital-integrated circuits(ICs).In this study,a method for modeling TID effects in complementary metaloxide semiconductor(CMOS)digital ICs based on the input/output buffer information specification(IBIS)was proposed.The digital IC was first divided into three parts based on its internal structure:the input buffer,output buffer,and functional area.Each of these three parts was separately modeled.Using the IBIS model,the transistor V-I characteristic curves of the buffers were processed,and the physical parameters were extracted and modeled using VHDL-AMS.In the functional area,logic functions were modeled in VHDL according to the data sheet.A golden digital IC model was developed by combining the input buffer,output buffer,and functional area models.Furthermore,the golden ratio was reconstructed based on TID experimental data,enabling the assessment of TID effects on the threshold voltage,carrier mobility,and time series of the digital IC.TID experiments were conducted using a CMOS non-inverting multiplexer,NC7SZ157,and the results were compared with the simulation results,which showed that the relative errors were less than 2%at each dose point.This confirms the practicality and accuracy of the proposed modeling method.The TID effect model for digital ICs developed using this modeling technique includes both the logical function of the IC and changes in electrical properties and functional degradation impacted by TID,which has potential applications in the design of radiation-hardening tolerance in digital ICs.展开更多
The first domestic 1×10^6rad(Si) total dose hardened 1.2μm partially depleted silicon-on-insulator (PDSOI) 64k SRAM fabricated in SIMOX is demonstrated.The address access time is independent of temperature f...The first domestic 1×10^6rad(Si) total dose hardened 1.2μm partially depleted silicon-on-insulator (PDSOI) 64k SRAM fabricated in SIMOX is demonstrated.The address access time is independent of temperature from -55 to 125℃ and independent of radiation up to 1×10^6rad(Si) for the supply voltage VDD.The standby current is 0.65μA before the total dose of radiation and is only 0.80mA after radiation exposure,which is much better than the specified 10mA.The operating power supply current is 33.0mA before and only 38.1mA afterward,which is much better than the specified 100mA.展开更多
Both nMOS and pMOS transistors with two-edged and multi-finger layouts are fabricated in a standard commercial 0.6μm CMOS/bulk process to study their total ionizing dose (TID) radiation effects. The leakage current...Both nMOS and pMOS transistors with two-edged and multi-finger layouts are fabricated in a standard commercial 0.6μm CMOS/bulk process to study their total ionizing dose (TID) radiation effects. The leakage current, threshold voltage shift, and transconductance of the devices are monitored before and after T-ray irradiation. Different device bias conditions are used during irradiation. The experiment results show that TID radiation effects on nMOS devices are very sensitive to their layout structures. The impact of the layout on TID effects on pMOS devices is slight and can be neglected.展开更多
The first domestic total dose hardened 2μm partially depleted silicon-on-insulator (PDSOI) CMOS 3-line to 8- line decoder fabricated in SIMOX is demonstrated. The radiation performance is characterized by transisto...The first domestic total dose hardened 2μm partially depleted silicon-on-insulator (PDSOI) CMOS 3-line to 8- line decoder fabricated in SIMOX is demonstrated. The radiation performance is characterized by transistor threshold voltage shifts,circuit static leakage currents,and I-V curves as a function of total dose up to 3× 10^5rad(Si). The worst case threshold voltage shifts of the front channels are less than 20mV for nMOS transistors at 3 × 10^5rad(Si) and follow-up irradiation and less than 70mV for the pMOS transistors. Furthermore, no significant radiation induced leakage currents and functional degeneration are observed.展开更多
The synergistic effect of total ionizing dose(TID) on single event effect(SEE) in SiGe heterojunction bipolar transistor(HBT) is investigated in a series of experiments. The SiGe HBTs after being exposed to 60 C...The synergistic effect of total ionizing dose(TID) on single event effect(SEE) in SiGe heterojunction bipolar transistor(HBT) is investigated in a series of experiments. The SiGe HBTs after being exposed to 60 Co g irradiation are struck by pulsed laser to simulate SEE. The SEE transient currents and collected charges of the un-irradiated device are compared with those of the devices which are irradiated at high and low dose rate with various biases. The results show that the SEE damage to un-irradiated device is more serious than that to irradiated SiGe HBT at a low applied voltage of laser test. In addition, the g irradiations at forward and all-grounded bias have an obvious influence on SEE in the SiGe HBT, but the synergistic effect after cutting off the g irradiation is not significant. The influence of positive oxide-trap charges induced by TID on the distortion of electric field in SEE is the major factor of the synergistic effect. Moreover, the recombination of interface traps also plays a role in charge collection.展开更多
Machine learning methods have proven to be powerful in various research fields.In this paper,we show that research on radiation effects could benefit from such methods and present a machine learning-based scientific d...Machine learning methods have proven to be powerful in various research fields.In this paper,we show that research on radiation effects could benefit from such methods and present a machine learning-based scientific discovery approach.The total ionizing dose(TID)effects usually cause gain degradation of bipolar junction transistors(BJTs),leading to functional failures of bipolar integrated circuits.Currently,many experiments of TID effects on BJTs have been conducted at different laboratories worldwide,producing a large amount of experimental data which provides a wealth of information.However,it is difficult to utilize these data effectively.In this study,we proposed a new artificial neural network(ANN)approach to analyze the experimental data of TID effects on BJTs An ANN model was built and trained using data collected from different experiments.The results indicate that the proposed ANN model has advantages in capturing nonlinear correlations and predicting the data.The trained ANN model suggests that the TID hardness of a BJT tends to increase with base current I.A possible cause for this finding was analyzed and confirmed through irradiation experiments.展开更多
Nitrogen ions of various doses are implanted into the buried oxide (BOX) of commercial silicon-on-insulator (SOI) materials, and subsequent annealings are carried out at various temperatures. The total dose radiat...Nitrogen ions of various doses are implanted into the buried oxide (BOX) of commercial silicon-on-insulator (SOI) materials, and subsequent annealings are carried out at various temperatures. The total dose radiation responses of the nitrogen-implanted SOI wafers are characterized by the high frequency capacitance-voltage (C-V) technique after irradi- ation using a Co-60 source. It is found that there exist relatively complex relationships between the radiation hardness of the nitrogen implanted BOX and the nitrogen implantation dose at different irradiation doses. The experimental results also suggest that a lower dose nitrogen implantation and a higher post-implantation annealing temperature are suitable for improving the radiation hardness of SOI wafer. Based on the measured C V data, secondary ion mass spectrometry (SIMS), and Fourier transform infrared (FTIR) spectroscopy, the total dose responses of the nitrogen-implanted SOI wafers are discussed.展开更多
On the basis of a detailed discussion of the development of total ionizing dose (TID) effect model, a new commercial-model-independent TID modeling approach for partially depleted silicon-on-insulator metal-oxide- s...On the basis of a detailed discussion of the development of total ionizing dose (TID) effect model, a new commercial-model-independent TID modeling approach for partially depleted silicon-on-insulator metal-oxide- semiconductor field effect transistors is developed. An exponential approximation is proposed to simplify the trap charge calculation. Irradiation experiments with 60Co gamma rays for IO and core devices are performed to validate the simulation results. An excellent agreement of measurement with the simulation results is observed.展开更多
The influence of combined total ionization dose(TID)and radiated electromagnetic interference(EMI)in a commercial analog-to-digital converter(ADC)was studied.The degradation of the direct-current response,the static p...The influence of combined total ionization dose(TID)and radiated electromagnetic interference(EMI)in a commercial analog-to-digital converter(ADC)was studied.The degradation of the direct-current response,the static parameters,and the dynamic parameters caused by the TID and EMI separately and synergistically is presented.The experimental results demonstrate that the increase in TID intensifies data error and the signal-tonoise ratio(SNR)degradation caused by radiated EMI.The cumulative distribution function of EMI failure with respect to data error and SNR with different TIDs was extracted.The decreasing trend of the threshold was acquired with a small sample size of five for each TID group.The result indicates that the ADC is more sensitive in a compound radiation environment.展开更多
This paper studies the total ionizing dose radiation effects on MOS (metal-oxide-semiconductor) transistors with normal and enclosed gate layout in a standard commercial CMOS (compensate MOS) bulk process. The lea...This paper studies the total ionizing dose radiation effects on MOS (metal-oxide-semiconductor) transistors with normal and enclosed gate layout in a standard commercial CMOS (compensate MOS) bulk process. The leakage current, threshold voltage shift, and transconductance of the devices were monitored before and after γ-ray irradiation. The parameters of the devices with different layout under different bias condition during irradiation at different total dose are investigated. The results show that the enclosed layout not only effectively eliminates the leakage but also improves the performance of threshold voltage and transconductance for NMOS (n-type channel MOS) transistors. The experimental results also indicate that analogue bias during irradiation is the worst case for enclosed gate NMOS. There is no evident different behaviour observed between normal PMOS (p-type channel MOS) transistors and enclosed gate PMOS transistors.展开更多
Total body irradiation(TBI)combined with chemotherapy prior to bone marrow transplantation(BMT)is used successfully for treatment leukemias.It need a high and homogeneous radiation dose to all target cells,dispersed I...Total body irradiation(TBI)combined with chemotherapy prior to bone marrow transplantation(BMT)is used successfully for treatment leukemias.It need a high and homogeneous radiation dose to all target cells,dispersed In the whole body.The lung is the most sensitive vital organ at risk in TBI.The lung dose must be within it's tolerable level.So,the determination of the lung dose is most Important for TBI.The determination of the lung dose is dependent on at least 8 parameters.In order to determine the effect of 8 parameters on the lung dose,using a system of phantom of Essen University hospital in F.R.Germany,a lot of measurements and a systematical investigation was made by varying 8 parameters,under the Essen translation TBI conditions.A analysis and discussion of results was made.展开更多
Annular gate nMOSFETs are frequently used in spaceborne integrated circuits due to their intrinsic good capability of resisting total ionizing dose (TID) effect. However, their capability of resisting the hot carrie...Annular gate nMOSFETs are frequently used in spaceborne integrated circuits due to their intrinsic good capability of resisting total ionizing dose (TID) effect. However, their capability of resisting the hot carrier effect (HCE) has also been proven to be very weak. In this paper, the reason why the annular gate nMOSFETs have good TID but bad HCE resistance is discussed in detail, and an improved design to locate the source contacts only along one side of the annular gate is used to weaken the HCE degradation. The good TID and HCE hardened capability of the design are verified by the experiments for I/O and core nMOSFETs in a 0.18 μm bulk CMOS technology. In addition, the shortcoming of this design is also discussed and the TID and the HCE characteristics of the replacers (the annular source nMOSFETs) are also studied to provide a possible alternative for the designers.展开更多
Total ionizing dose induced single transistor latchup effects for 130 nm partially depleted silicon-on-insulator (PDSOI) NMOSFETs with the bodies floating were studied in this work. The latchup phenomenon strongly c...Total ionizing dose induced single transistor latchup effects for 130 nm partially depleted silicon-on-insulator (PDSOI) NMOSFETs with the bodies floating were studied in this work. The latchup phenomenon strongly correlates with the bias configuration during irradiation. It is found that the high body doping concentration can make the devices less sensitive to the single transistor latchup effect, and the onset drain voltage at which latchup occurs can degrade as the total dose level rises. The mechanism of band-to-band tunneling (BBT) has been discussed. Two-dimensional simulations were conducted to evaluate the BBT effect. It is demonstrated that BBT combined with the positive trapped charge in the buried oxide (BOX) contributes a lot to the latchup effect.展开更多
The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors (nMOSFETs) is investigated. Experimental results show that hot-carrier degradati...The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors (nMOSFETs) is investigated. Experimental results show that hot-carrier degradations on ir- radiated narrow channel nMOSFETs are greater than those without irradiation. The reason is attributed to radiation-induced charge trapping in shallow trench isolation (STI). The electric field in the pinch-off region of the nMOSFET is enhanced by radiation-induced charge trapping in STI, resulting in a more severe hot-carrier effect.展开更多
The total dose effect of ^(60)Co γ-rays on 0.8μm H-gate partially depleted-silicon-on-insulator NMOS devices was investigated at different irradiation doses. The results show that the shift in saturation current at ...The total dose effect of ^(60)Co γ-rays on 0.8μm H-gate partially depleted-silicon-on-insulator NMOS devices was investigated at different irradiation doses. The results show that the shift in saturation current at high dose rate is greater than that at low dose rate, due to increase in interface-state density with decreasing dose rate; the scattering effect of interface state on electrons in the channel causes degradation in carrier mobility; and the body current and transconductance of the back gate enhance low-doserate sensitivity when the irradiation is under OFF-bias. A double transconductance peak is observed at 3 kGy(Si)under high dose rates.展开更多
An anomalous total dose effect that the long length device is more susceptible to total ionizing dose than the short one is observed with the 0.13?μm partially depleted silicon-on-insulator technology. The measured ...An anomalous total dose effect that the long length device is more susceptible to total ionizing dose than the short one is observed with the 0.13?μm partially depleted silicon-on-insulator technology. The measured results and 3D technology computer aided design simulations demonstrate that the devices with different channel lengths may exhibit an enhanced reverse short channel effect after radiation. It is ascribed to that the halo or pocket implants introduced in processes results in non-uniform channel doping profiles along the device length and trapped charges in the shallow trench isolation regions.展开更多
The pattern dependence in synergistic effects was studied in a 0.18 μm static random access memory(SRAM) circuit.Experiments were performed under two SEU test environments:3 Me V protons and heavy ions.Measured re...The pattern dependence in synergistic effects was studied in a 0.18 μm static random access memory(SRAM) circuit.Experiments were performed under two SEU test environments:3 Me V protons and heavy ions.Measured results show different trends.In heavy ion SEU test,the degradation in the peripheral circuitry also existed because the measured SEU cross section decreased regardless of the patterns written to the SRAM array.TCAD simulation was performed.TIDinduced degradation in n MOSFETs mainly induced the imprint effect in the SRAM cell,which is consistent with the measured results under the proton environment,but cannot explain the phenomena observed under heavy ion environment.A possible explanation could be the contribution from the radiation-induced GIDL in pMOSFETs.展开更多
Because of the discrete charge storage mechanism, charge trapping memory(CTM) technique is a good candidate for aerospace and military missions. The total ionization dose(TID) effects on CTM cells with Al2O3/HfO2/...Because of the discrete charge storage mechanism, charge trapping memory(CTM) technique is a good candidate for aerospace and military missions. The total ionization dose(TID) effects on CTM cells with Al2O3/HfO2/Al2O3(AHA) high-k gate stack structure under in-situ 10 keV x-rays are studied. The C-V characteristics at different radiation doses demonstrate that charge stored in the device continues to be leaked away during the irradiation,thereby inducing the shift of flat band voltage(V(fb)). The dc memory window shows insignificant changes, suggesting the existence of good P/E ability. Furthermore, the physical mechanisms of TID induced radiation damages in AHA-based CTM are analyzed.展开更多
文摘BACKGROUND Acetabular component positioning in total hip arthroplasty(THA)is of key importance to ensure satisfactory post-operative outcomes and to minimize the risk of complications.The majority of acetabular components are aligned freehand,without the use of navigation methods.Patient specific instruments(PSI)and three-dimensional(3D)printing of THA placement guides are increasingly used in primary THA to ensure optimal positioning.AIM To summarize the literature on 3D printing in THA and how they improve acetabular component alignment.METHODS PubMed was used to identify and access scientific studies reporting on different 3D printing methods used in THA.Eight studies with 236 hips in 228 patients were included.The studies could be divided into two main categories;3D printed models and 3D printed guides.RESULTS 3D printing in THA helped improve preoperative cup size planning and post-operative Harris hip scores between intervention and control groups(P=0.019,P=0.009).Otherwise,outcome measures were heterogeneous and thus difficult to compare.The overarching consensus between the studies is that the use of 3D guidance tools can assist in improving THA cup positioning and reduce the need for revision THA and the associated costs.CONCLUSION The implementation of 3D printing and PSI for primary THA can significantly improve the positioning accuracy of the acetabular cup component and reduce the number of complications caused by malpositioning.
基金This work was supported by the special fund of the State Key Laboratory of Intense Pulsed Radiation Simulation and Effect(No.SKLIPR2011).
文摘Simulating the total ionizing dose(TID)of an electrical system using transistor-level models can be difficult and expensive,particularly for digital-integrated circuits(ICs).In this study,a method for modeling TID effects in complementary metaloxide semiconductor(CMOS)digital ICs based on the input/output buffer information specification(IBIS)was proposed.The digital IC was first divided into three parts based on its internal structure:the input buffer,output buffer,and functional area.Each of these three parts was separately modeled.Using the IBIS model,the transistor V-I characteristic curves of the buffers were processed,and the physical parameters were extracted and modeled using VHDL-AMS.In the functional area,logic functions were modeled in VHDL according to the data sheet.A golden digital IC model was developed by combining the input buffer,output buffer,and functional area models.Furthermore,the golden ratio was reconstructed based on TID experimental data,enabling the assessment of TID effects on the threshold voltage,carrier mobility,and time series of the digital IC.TID experiments were conducted using a CMOS non-inverting multiplexer,NC7SZ157,and the results were compared with the simulation results,which showed that the relative errors were less than 2%at each dose point.This confirms the practicality and accuracy of the proposed modeling method.The TID effect model for digital ICs developed using this modeling technique includes both the logical function of the IC and changes in electrical properties and functional degradation impacted by TID,which has potential applications in the design of radiation-hardening tolerance in digital ICs.
文摘The first domestic 1×10^6rad(Si) total dose hardened 1.2μm partially depleted silicon-on-insulator (PDSOI) 64k SRAM fabricated in SIMOX is demonstrated.The address access time is independent of temperature from -55 to 125℃ and independent of radiation up to 1×10^6rad(Si) for the supply voltage VDD.The standby current is 0.65μA before the total dose of radiation and is only 0.80mA after radiation exposure,which is much better than the specified 10mA.The operating power supply current is 33.0mA before and only 38.1mA afterward,which is much better than the specified 100mA.
文摘Both nMOS and pMOS transistors with two-edged and multi-finger layouts are fabricated in a standard commercial 0.6μm CMOS/bulk process to study their total ionizing dose (TID) radiation effects. The leakage current, threshold voltage shift, and transconductance of the devices are monitored before and after T-ray irradiation. Different device bias conditions are used during irradiation. The experiment results show that TID radiation effects on nMOS devices are very sensitive to their layout structures. The impact of the layout on TID effects on pMOS devices is slight and can be neglected.
文摘The first domestic total dose hardened 2μm partially depleted silicon-on-insulator (PDSOI) CMOS 3-line to 8- line decoder fabricated in SIMOX is demonstrated. The radiation performance is characterized by transistor threshold voltage shifts,circuit static leakage currents,and I-V curves as a function of total dose up to 3× 10^5rad(Si). The worst case threshold voltage shifts of the front channels are less than 20mV for nMOS transistors at 3 × 10^5rad(Si) and follow-up irradiation and less than 70mV for the pMOS transistors. Furthermore, no significant radiation induced leakage currents and functional degeneration are observed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61704127 and 61574171)the Fundamental Research Funds for the Central Universities,China(Grant No.XJS17067)
文摘The synergistic effect of total ionizing dose(TID) on single event effect(SEE) in SiGe heterojunction bipolar transistor(HBT) is investigated in a series of experiments. The SiGe HBTs after being exposed to 60 Co g irradiation are struck by pulsed laser to simulate SEE. The SEE transient currents and collected charges of the un-irradiated device are compared with those of the devices which are irradiated at high and low dose rate with various biases. The results show that the SEE damage to un-irradiated device is more serious than that to irradiated SiGe HBT at a low applied voltage of laser test. In addition, the g irradiations at forward and all-grounded bias have an obvious influence on SEE in the SiGe HBT, but the synergistic effect after cutting off the g irradiation is not significant. The influence of positive oxide-trap charges induced by TID on the distortion of electric field in SEE is the major factor of the synergistic effect. Moreover, the recombination of interface traps also plays a role in charge collection.
基金supported by the National Natural Science Foundation of China (Nos. 11690040 and 11690043)。
文摘Machine learning methods have proven to be powerful in various research fields.In this paper,we show that research on radiation effects could benefit from such methods and present a machine learning-based scientific discovery approach.The total ionizing dose(TID)effects usually cause gain degradation of bipolar junction transistors(BJTs),leading to functional failures of bipolar integrated circuits.Currently,many experiments of TID effects on BJTs have been conducted at different laboratories worldwide,producing a large amount of experimental data which provides a wealth of information.However,it is difficult to utilize these data effectively.In this study,we proposed a new artificial neural network(ANN)approach to analyze the experimental data of TID effects on BJTs An ANN model was built and trained using data collected from different experiments.The results indicate that the proposed ANN model has advantages in capturing nonlinear correlations and predicting the data.The trained ANN model suggests that the TID hardness of a BJT tends to increase with base current I.A possible cause for this finding was analyzed and confirmed through irradiation experiments.
文摘Nitrogen ions of various doses are implanted into the buried oxide (BOX) of commercial silicon-on-insulator (SOI) materials, and subsequent annealings are carried out at various temperatures. The total dose radiation responses of the nitrogen-implanted SOI wafers are characterized by the high frequency capacitance-voltage (C-V) technique after irradi- ation using a Co-60 source. It is found that there exist relatively complex relationships between the radiation hardness of the nitrogen implanted BOX and the nitrogen implantation dose at different irradiation doses. The experimental results also suggest that a lower dose nitrogen implantation and a higher post-implantation annealing temperature are suitable for improving the radiation hardness of SOI wafer. Based on the measured C V data, secondary ion mass spectrometry (SIMS), and Fourier transform infrared (FTIR) spectroscopy, the total dose responses of the nitrogen-implanted SOI wafers are discussed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61404151 and 61574153
文摘On the basis of a detailed discussion of the development of total ionizing dose (TID) effect model, a new commercial-model-independent TID modeling approach for partially depleted silicon-on-insulator metal-oxide- semiconductor field effect transistors is developed. An exponential approximation is proposed to simplify the trap charge calculation. Irradiation experiments with 60Co gamma rays for IO and core devices are performed to validate the simulation results. An excellent agreement of measurement with the simulation results is observed.
文摘The influence of combined total ionization dose(TID)and radiated electromagnetic interference(EMI)in a commercial analog-to-digital converter(ADC)was studied.The degradation of the direct-current response,the static parameters,and the dynamic parameters caused by the TID and EMI separately and synergistically is presented.The experimental results demonstrate that the increase in TID intensifies data error and the signal-tonoise ratio(SNR)degradation caused by radiated EMI.The cumulative distribution function of EMI failure with respect to data error and SNR with different TIDs was extracted.The decreasing trend of the threshold was acquired with a small sample size of five for each TID group.The result indicates that the ADC is more sensitive in a compound radiation environment.
基金Project supported by the National Natural Science Foundation of China (Grant No 6037202/F010204).
文摘This paper studies the total ionizing dose radiation effects on MOS (metal-oxide-semiconductor) transistors with normal and enclosed gate layout in a standard commercial CMOS (compensate MOS) bulk process. The leakage current, threshold voltage shift, and transconductance of the devices were monitored before and after γ-ray irradiation. The parameters of the devices with different layout under different bias condition during irradiation at different total dose are investigated. The results show that the enclosed layout not only effectively eliminates the leakage but also improves the performance of threshold voltage and transconductance for NMOS (n-type channel MOS) transistors. The experimental results also indicate that analogue bias during irradiation is the worst case for enclosed gate NMOS. There is no evident different behaviour observed between normal PMOS (p-type channel MOS) transistors and enclosed gate PMOS transistors.
文摘Total body irradiation(TBI)combined with chemotherapy prior to bone marrow transplantation(BMT)is used successfully for treatment leukemias.It need a high and homogeneous radiation dose to all target cells,dispersed In the whole body.The lung is the most sensitive vital organ at risk in TBI.The lung dose must be within it's tolerable level.So,the determination of the lung dose is most Important for TBI.The determination of the lung dose is dependent on at least 8 parameters.In order to determine the effect of 8 parameters on the lung dose,using a system of phantom of Essen University hospital in F.R.Germany,a lot of measurements and a systematical investigation was made by varying 8 parameters,under the Essen translation TBI conditions.A analysis and discussion of results was made.
基金supported by the Key Program of the National Natural Science Foundation of China(Grant No.60836004)the National Natural Science Foundation of China(Grant Nos.61006070 and 61076025)
文摘Annular gate nMOSFETs are frequently used in spaceborne integrated circuits due to their intrinsic good capability of resisting total ionizing dose (TID) effect. However, their capability of resisting the hot carrier effect (HCE) has also been proven to be very weak. In this paper, the reason why the annular gate nMOSFETs have good TID but bad HCE resistance is discussed in detail, and an improved design to locate the source contacts only along one side of the annular gate is used to weaken the HCE degradation. The good TID and HCE hardened capability of the design are verified by the experiments for I/O and core nMOSFETs in a 0.18 μm bulk CMOS technology. In addition, the shortcoming of this design is also discussed and the TID and the HCE characteristics of the replacers (the annular source nMOSFETs) are also studied to provide a possible alternative for the designers.
基金Project supported by Shanghai Municipal Natural Science Foundation,China(Grant No.15ZR1447100)
文摘Total ionizing dose induced single transistor latchup effects for 130 nm partially depleted silicon-on-insulator (PDSOI) NMOSFETs with the bodies floating were studied in this work. The latchup phenomenon strongly correlates with the bias configuration during irradiation. It is found that the high body doping concentration can make the devices less sensitive to the single transistor latchup effect, and the onset drain voltage at which latchup occurs can degrade as the total dose level rises. The mechanism of band-to-band tunneling (BBT) has been discussed. Two-dimensional simulations were conducted to evaluate the BBT effect. It is demonstrated that BBT combined with the positive trapped charge in the buried oxide (BOX) contributes a lot to the latchup effect.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475255,U1532261 and 11505282
文摘The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors (nMOSFETs) is investigated. Experimental results show that hot-carrier degradations on ir- radiated narrow channel nMOSFETs are greater than those without irradiation. The reason is attributed to radiation-induced charge trapping in shallow trench isolation (STI). The electric field in the pinch-off region of the nMOSFET is enhanced by radiation-induced charge trapping in STI, resulting in a more severe hot-carrier effect.
基金supported by the National Natural Science Foundation of China(No.61376099)the Foundation for Fundamental Research of China(No.JSZL2016110B003)the Major Fundamental Research Program of Shaanxi(No.2017ZDJC-26)
文摘The total dose effect of ^(60)Co γ-rays on 0.8μm H-gate partially depleted-silicon-on-insulator NMOS devices was investigated at different irradiation doses. The results show that the shift in saturation current at high dose rate is greater than that at low dose rate, due to increase in interface-state density with decreasing dose rate; the scattering effect of interface state on electrons in the channel causes degradation in carrier mobility; and the body current and transconductance of the back gate enhance low-doserate sensitivity when the irradiation is under OFF-bias. A double transconductance peak is observed at 3 kGy(Si)under high dose rates.
基金Supported by the Weapon Equipment Pre-Research Foundation of China under Grant No 9140A11020114ZK34147the Shanghai Municipal Natural Science Foundation under Grant Nos 15ZR1447100 and 15ZR1447200
文摘An anomalous total dose effect that the long length device is more susceptible to total ionizing dose than the short one is observed with the 0.13?μm partially depleted silicon-on-insulator technology. The measured results and 3D technology computer aided design simulations demonstrate that the devices with different channel lengths may exhibit an enhanced reverse short channel effect after radiation. It is ascribed to that the halo or pocket implants introduced in processes results in non-uniform channel doping profiles along the device length and trapped charges in the shallow trench isolation regions.
基金Project supported by the National Natural Science Foundation of China(Grant No.U1532261)
文摘The pattern dependence in synergistic effects was studied in a 0.18 μm static random access memory(SRAM) circuit.Experiments were performed under two SEU test environments:3 Me V protons and heavy ions.Measured results show different trends.In heavy ion SEU test,the degradation in the peripheral circuitry also existed because the measured SEU cross section decreased regardless of the patterns written to the SRAM array.TCAD simulation was performed.TIDinduced degradation in n MOSFETs mainly induced the imprint effect in the SRAM cell,which is consistent with the measured results under the proton environment,but cannot explain the phenomena observed under heavy ion environment.A possible explanation could be the contribution from the radiation-induced GIDL in pMOSFETs.
基金Supported by the National Natural Science Foundation of China under Grant No 616340084the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No 2014101+1 种基金the International Cooperation Project of Chinese Academy of Sciencesthe Austrian-Chinese Cooperative R&D Projects under Grant No 172511KYSB20150006
文摘Because of the discrete charge storage mechanism, charge trapping memory(CTM) technique is a good candidate for aerospace and military missions. The total ionization dose(TID) effects on CTM cells with Al2O3/HfO2/Al2O3(AHA) high-k gate stack structure under in-situ 10 keV x-rays are studied. The C-V characteristics at different radiation doses demonstrate that charge stored in the device continues to be leaked away during the irradiation,thereby inducing the shift of flat band voltage(V(fb)). The dc memory window shows insignificant changes, suggesting the existence of good P/E ability. Furthermore, the physical mechanisms of TID induced radiation damages in AHA-based CTM are analyzed.