2016 IEEE 22nd International Symposium on On-Line Testing and Robust System Design (IOLTS), 2016
This paper analyzes the single event transient (SET) response of a single event latchup (SEL) pro... more This paper analyzes the single event transient (SET) response of a single event latchup (SEL) protection switch (SPS) designed in the 130 and 250 nm bulk CMOS technologies. The analysis has been conducted through the SPICE simulations, using the standard double exponential current source as the SET model. It has been confirmed that the 130 nm SPS cell is more susceptible to SETs than the 250 nm version, i.e. the 130 nm SPS cell has exhibited significantly lower critical charge. Based on the simulation results, an analytical model for estimating the critical charge in terms of the transistor size, number of load cells, and duration of the SET current pulse, has been derived. Use of the proposed critical charge model simplifies the analysis of the SPS cell's susceptibility to SETs for custom designs.
The circuit-level simulation analysis of the single event transient response of an on-chip single... more The circuit-level simulation analysis of the single event transient response of an on-chip single event latchup protection switch (SPS cell), previously designed and developed in the IHP 250 nm CMOS process, is presented. The SPS cell provides the latchup protection for standard cells on the principle of power domain control. It is based on a sensing/ driving PMOS transistor which acts both as a latchup sensor and a driver for the standard cells, and includes additional PMOS and NMOS transistors for controlling the sensing/ driving transistor and interfacing to the external control logic. The previous work has confirmed the SPS cell's functionality in the case of single event latchup, and the experimental investigation has proven that the SPS cell is immune to single event latchup for LET values up to 74.8 MeV cm 2 /mg. This case study extends the previous research by introducing the circuit-level simulation of the SPS cell's response to the single event transients (SETs). Using the square pulse current as a SET model, the amplitude and duration of the SET-induced voltage pulses at the SPS cell's outputs have been analyzed with respect to the injected charge, operating temperature, supply voltage, load (number of standard cells connected to the SPS cell) and sensing/driving transistor's channel width. The results have shown that the immunity of the SPS cell to SETs can be significantly enhanced by connecting a larger number of standard cells to the SPS cell and increasing the sensing/driving transistor's size, without any area overhead. An analytical expression for calculating the critical charge in terms of the transistor size and the number of standard cells connected to the SPS cell has been derived. Moreover, the SPS cell can be used as a SET sensor for detecting the levels of injected charge which cannot be mitigated by the increase of transistor size and load, and in conjunction with the external control logic it could be possible to measure the SET duration and perform online corrections of the SET-induced faults in the standard cells supplied by the SPS cell.
17th International Symposium on Design and Diagnostics of Electronic Circuits & Systems, 2014
ABSTRACT A low-cost switching system based on PIC 18F4550 microcontroller, which enables the succ... more ABSTRACT A low-cost switching system based on PIC 18F4550 microcontroller, which enables the successive measurement of both electrical characteristics (midgap-subthreshold technique, MGT) and charge-pumping currents (charge-pumping technique, CPT) of metal-oxide-semiconductor field-effect transistor (MOSFET) has been developed. The system can be used for switching between MGT and CPT instead of the expensive commercial switching systems. It has been used for characterization (MGT and CPT measurements) of RADFETs with the oxide thicknesses of 0.4 µm and 1 µm.
A complete study of the defects created in the gate oxide and at the gate oxide/substrate interfa... more A complete study of the defects created in the gate oxide and at the gate oxide/substrate interface of metal-oxide-semiconductor transistors with thick gate oxide (t ox > 10 nm) during high electric field stress, and the mechanisms responsible for these defects creation have been given. In addition, some results of positive/negative high electric field stress with constant gate voltage of commercial n-channel power metal-oxide-semiconductor transistors with thick gate oxide of 100 nm, have been explained using this study.
p-channel metal-oxide-semiconductor (pMOS) dosimetric transistors are unique radiation dosimeters... more p-channel metal-oxide-semiconductor (pMOS) dosimetric transistors are unique radiation dosimeters that have an extremely small size (the dimensions of the sensor element are less than 1 mm × 1 mm) and allow the measurement of dose in vivo in real time, which are especially important characteristics for radiotherapy. The isothermal, isochronal and UV annealing of pMOS dosimetric transistors have been investigated. The obtained results have shown that the high temperature annealing for thin and UV annealing for thick oxide, respectively, are very useful tools for radiation defect annealing. The spontaneous annealing is high, as a probable consequence of gate material (Al gate). The investigation has also shown that not only the threshold-voltage behaviour but also the behaviour of radiation defects in the oxide and at the oxide interface has to be known. The modelling of isothermal annealing at different temperatures has been performed.
Indirect flat panel imagers have been developed for digital radiography, fluoroscopy and mammogra... more Indirect flat panel imagers have been developed for digital radiography, fluoroscopy and mammography, and are now in clinical use. Screens made from columnar structured cesium iodide (CsI) scintillators doped with thallium have been used extensively in these detectors. The purpose of this article is to investigate the effect of screen optics, e.g., light escape efficiency versus depth, on gain fluctuation noise, expressed as the Swank factor. Our goal is to obtain results useful in optimizing screens for digital radiography systems. Experimental measurements from structured CsI samples were used to derive their screen optics properties, and the same methods can also be applied to powder screens. CsI screens, all of the same thickness but with different optical designs and manufacturing techniques, were obtained from Hamamatsu Photonics Corporation. The pulse height spectra (PHS) of the screens were measured at different x-ray energies. A theoretical model was developed for the light escape efficiency and a method for deriving light escape efficiency versus depth from experimental PHS measurements was implemented and applied to the CsI screens. The results showed that the light escape efficiency varies essentially linearly as a function of depth in the CsI samples, and that the magnitude of variation is relatively small, leading to a high Swank factor.
Japanese Journal of Applied Physics Pt 1 Regular Papers Short Notes, Mar 1, 1995
The formative time for different values of afterglow period with/without positive bias on the ele... more The formative time for different values of afterglow period with/without positive bias on the electrodes in nitrogen-filled tube has been investigated. The obtained values for average formative time delay which is determined as the difference between average total time delay of electrical breakdown and standard deviation are in accordance with those evaluated from the Laue distribution. The good agreement of formative time values which are determined by these methods is observed in the case when the electrical breakdown is mostly initiated by secondary electrons from the cathode induced by positive ions which remained from the previous discharge.
Page 1. Influence of ionizing radiation and hot carrier injection on metal-oxide-semiconductor tr... more Page 1. Influence of ionizing radiation and hot carrier injection on metal-oxide-semiconductor transistors This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2008 J. Phys. D: Appl. Phys. 41 023001 ...
Journal of Physics D Applied Physics, Oct 29, 2008
Experimentally measured electrical breakdown time delay data versus the afterglow period (represe... more Experimentally measured electrical breakdown time delay data versus the afterglow period (representing ‘memory curves’) for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar have been shown. The influence of N(4S) nitrogen atoms on secondary electron emission from the cathode (the SEE process) in late afterglow has been discussed. N(4S) atom concentration decay over relaxation time τ, N(4S)(τ), has been analysed by a numerical model and two analytical models. N(4S) decay analytical models are combined with different yield models that describe the SEE process by N(4S) and these combinations are employed to fit the experimental data. It has been shown that in late afterglow solving of very simple analytical equations instead of numerical solving of partial differential equations for N(4S)(τ) fitting can be used and that the combination of the first and the second order of the SEE process by N(4S) in yield modelling should be used in the case of 13.3 mbar pressure.
Advances in Clinical and Experimental Medicine, 2015
Background. Microwaves from mobile phones are one of the environmental toxicants that are capable... more Background. Microwaves from mobile phones are one of the environmental toxicants that are capable of compromising male fertility by inducing oxidative stress and apoptosis in the testes. Melatonin is a lipophilic tryptophan indole amine and a potent antioxidant. Objectives. The aim of the study was to evaluate the effect of melatonin treatment on oxidative stress parameters and DNA fragmentation in the testicular tissue of rats exposed to microwave radiation (4 h/day). Material and Methods. Adult Wistar rats were divided in 4 groups: I -treated with saline; II -treated with melatonin; III -exposed to microwaves; IV -exposed to microwaves and treated with melatonin. The melatonin (2 mg/kg ip) was administered daily. The animals were sacrificed after 20, 40 and 60 days. Results. Melatonin treatment prevented previously registered increases in malondialdehyde after only 20 days. Furthermore, it reversed the effects of microwave exposure on xanthine oxidase (after 40 days) and acid-DNase activity (after 20 days). However, neither protein carbonyl content nor catalase and alkaline Dnase activity were changed due to melatonin treatment. Conclusions. Melatonin exerts potent antioxidant effects in the testes of rats exposed to microwaves by decreasing the intensity of oxidative stress; it also reduces DNA fragmentation (Adv Clin Exp Med 2015, 24, 3, 429-436).
2015 IEEE 18th International Symposium on Design and Diagnostics of Electronic Circuits & Systems, 2015
ABSTRACT A single event latchup protection switch (SPS) has been developed in the IHP 250 nm bulk... more ABSTRACT A single event latchup protection switch (SPS) has been developed in the IHP 250 nm bulk CMOS technology. The SPS has been designed as a standard library cell intended for implementation in the radiation-tolerant application specific integrated circuits (ASICs). It provides detection of single event latchup and subsequent shutdown of power supply to critical elements within the chip to restore the normal operation. However, the SPS cell might be also susceptible to single event transients. In that regard, this work presents the simulation-based analysis of the response of SPS cell in the case of single event transients. The dependence of the single event transient response with respect to the injected charge, supply voltage, load and sensing transistor's size has been analyzed.
Proceedings of International Conference on Microelectronics, 1995
The behaviour of commercial n-channel power VDMOSFETs during γ-ray irradiation and subsequent ann... more The behaviour of commercial n-channel power VDMOSFETs during γ-ray irradiation and subsequent annealing at elevated temperature is investigated. The creation of positive oxide-trap charge dominates during irradiation, leading to negative threshold voltage shift. So called `latent' interface-trap buildup, observed during annealing after initial apparent saturation of interface-trap density, is identified as the main contributor to the threshold voltage rebound. At
1995 International Semiconductor Conference. CAS '95 Proceedings, 1995
The behaviour of the threshold voltage in commercial n-channel power VDMOSFETs during biased ther... more The behaviour of the threshold voltage in commercial n-channel power VDMOSFETs during biased thermal annealing, following γ-ray radiation exposure, is investigated. It is found that `rebound' effect, observed in transistors irradiated and annealed with positive gate bias, is mainly due to the `latent' interface-trap generation. Possible mechanism for latent interface-trap buildup is proposed
This paper presents results of a study of post-irradiation behavior of commercial n-channel power... more This paper presents results of a study of post-irradiation behavior of commercial n-channel power VDMOSFETs. Gamma-ray irradiated transistors have been subjected to the series of isothermal and isochronal annealings. The response of EFL1N10 devices, manufactured by domestic vendor, Ei-Microelectronics, is compared to that of Intersil's IRF510 devices. It has been found that during isothermal annealing EFL1N10 devices exhibit the so called latent interface-trap buildup (LITB), while such phenomenon hasn't been observed in IRF510. Additional switching temperature annealing and switching bias annealing experiments performed on EFL1N10 may prove useful in revealing details of LITB
The behavior of radiation-induced fixed traps (FTs) in gate oxide and radiation-induced switching... more The behavior of radiation-induced fixed traps (FTs) in gate oxide and radiation-induced switching traps (STs) near and at the gate oxide/substrate interface during irradiation up to high absorbed doses has been considered. The zero-bias voltage regime, the simplest and most popular solution in practice, was chosen. Indeed, it is very difficult to predict the creation of radiation defects in the case of low electric fields, because there is a compromise between the external low electric fields induced by work function differences and the internal electrical fields induced by radiation-induced charged defects in the oxide. It was shown that the density of FTs is higher than the density of STs for lower absorbed doses, though the trend is reversed for doses greater than 700Gy. Although the number of FTs is much higher than the number of STs, many FTs are located in the bulk, far from the oxide/semiconductor interface and their influence on channel carriers is much smaller than the influence of STs that are located closer to the channel. The equation for fitting the threshold voltage components induced by FTs (ΔVft) and by STs (ΔVst) is proposed and very good fittings are obtained. It is shown that five experimental irradiation points are sufficient to draw a good conclusion about the values of the fitting parameters, i.e., the voltage saturation values and the degree of linearity.
2016 IEEE 22nd International Symposium on On-Line Testing and Robust System Design (IOLTS), 2016
This paper analyzes the single event transient (SET) response of a single event latchup (SEL) pro... more This paper analyzes the single event transient (SET) response of a single event latchup (SEL) protection switch (SPS) designed in the 130 and 250 nm bulk CMOS technologies. The analysis has been conducted through the SPICE simulations, using the standard double exponential current source as the SET model. It has been confirmed that the 130 nm SPS cell is more susceptible to SETs than the 250 nm version, i.e. the 130 nm SPS cell has exhibited significantly lower critical charge. Based on the simulation results, an analytical model for estimating the critical charge in terms of the transistor size, number of load cells, and duration of the SET current pulse, has been derived. Use of the proposed critical charge model simplifies the analysis of the SPS cell's susceptibility to SETs for custom designs.
The circuit-level simulation analysis of the single event transient response of an on-chip single... more The circuit-level simulation analysis of the single event transient response of an on-chip single event latchup protection switch (SPS cell), previously designed and developed in the IHP 250 nm CMOS process, is presented. The SPS cell provides the latchup protection for standard cells on the principle of power domain control. It is based on a sensing/ driving PMOS transistor which acts both as a latchup sensor and a driver for the standard cells, and includes additional PMOS and NMOS transistors for controlling the sensing/ driving transistor and interfacing to the external control logic. The previous work has confirmed the SPS cell's functionality in the case of single event latchup, and the experimental investigation has proven that the SPS cell is immune to single event latchup for LET values up to 74.8 MeV cm 2 /mg. This case study extends the previous research by introducing the circuit-level simulation of the SPS cell's response to the single event transients (SETs). Using the square pulse current as a SET model, the amplitude and duration of the SET-induced voltage pulses at the SPS cell's outputs have been analyzed with respect to the injected charge, operating temperature, supply voltage, load (number of standard cells connected to the SPS cell) and sensing/driving transistor's channel width. The results have shown that the immunity of the SPS cell to SETs can be significantly enhanced by connecting a larger number of standard cells to the SPS cell and increasing the sensing/driving transistor's size, without any area overhead. An analytical expression for calculating the critical charge in terms of the transistor size and the number of standard cells connected to the SPS cell has been derived. Moreover, the SPS cell can be used as a SET sensor for detecting the levels of injected charge which cannot be mitigated by the increase of transistor size and load, and in conjunction with the external control logic it could be possible to measure the SET duration and perform online corrections of the SET-induced faults in the standard cells supplied by the SPS cell.
17th International Symposium on Design and Diagnostics of Electronic Circuits & Systems, 2014
ABSTRACT A low-cost switching system based on PIC 18F4550 microcontroller, which enables the succ... more ABSTRACT A low-cost switching system based on PIC 18F4550 microcontroller, which enables the successive measurement of both electrical characteristics (midgap-subthreshold technique, MGT) and charge-pumping currents (charge-pumping technique, CPT) of metal-oxide-semiconductor field-effect transistor (MOSFET) has been developed. The system can be used for switching between MGT and CPT instead of the expensive commercial switching systems. It has been used for characterization (MGT and CPT measurements) of RADFETs with the oxide thicknesses of 0.4 µm and 1 µm.
A complete study of the defects created in the gate oxide and at the gate oxide/substrate interfa... more A complete study of the defects created in the gate oxide and at the gate oxide/substrate interface of metal-oxide-semiconductor transistors with thick gate oxide (t ox > 10 nm) during high electric field stress, and the mechanisms responsible for these defects creation have been given. In addition, some results of positive/negative high electric field stress with constant gate voltage of commercial n-channel power metal-oxide-semiconductor transistors with thick gate oxide of 100 nm, have been explained using this study.
p-channel metal-oxide-semiconductor (pMOS) dosimetric transistors are unique radiation dosimeters... more p-channel metal-oxide-semiconductor (pMOS) dosimetric transistors are unique radiation dosimeters that have an extremely small size (the dimensions of the sensor element are less than 1 mm × 1 mm) and allow the measurement of dose in vivo in real time, which are especially important characteristics for radiotherapy. The isothermal, isochronal and UV annealing of pMOS dosimetric transistors have been investigated. The obtained results have shown that the high temperature annealing for thin and UV annealing for thick oxide, respectively, are very useful tools for radiation defect annealing. The spontaneous annealing is high, as a probable consequence of gate material (Al gate). The investigation has also shown that not only the threshold-voltage behaviour but also the behaviour of radiation defects in the oxide and at the oxide interface has to be known. The modelling of isothermal annealing at different temperatures has been performed.
Indirect flat panel imagers have been developed for digital radiography, fluoroscopy and mammogra... more Indirect flat panel imagers have been developed for digital radiography, fluoroscopy and mammography, and are now in clinical use. Screens made from columnar structured cesium iodide (CsI) scintillators doped with thallium have been used extensively in these detectors. The purpose of this article is to investigate the effect of screen optics, e.g., light escape efficiency versus depth, on gain fluctuation noise, expressed as the Swank factor. Our goal is to obtain results useful in optimizing screens for digital radiography systems. Experimental measurements from structured CsI samples were used to derive their screen optics properties, and the same methods can also be applied to powder screens. CsI screens, all of the same thickness but with different optical designs and manufacturing techniques, were obtained from Hamamatsu Photonics Corporation. The pulse height spectra (PHS) of the screens were measured at different x-ray energies. A theoretical model was developed for the light escape efficiency and a method for deriving light escape efficiency versus depth from experimental PHS measurements was implemented and applied to the CsI screens. The results showed that the light escape efficiency varies essentially linearly as a function of depth in the CsI samples, and that the magnitude of variation is relatively small, leading to a high Swank factor.
Japanese Journal of Applied Physics Pt 1 Regular Papers Short Notes, Mar 1, 1995
The formative time for different values of afterglow period with/without positive bias on the ele... more The formative time for different values of afterglow period with/without positive bias on the electrodes in nitrogen-filled tube has been investigated. The obtained values for average formative time delay which is determined as the difference between average total time delay of electrical breakdown and standard deviation are in accordance with those evaluated from the Laue distribution. The good agreement of formative time values which are determined by these methods is observed in the case when the electrical breakdown is mostly initiated by secondary electrons from the cathode induced by positive ions which remained from the previous discharge.
Page 1. Influence of ionizing radiation and hot carrier injection on metal-oxide-semiconductor tr... more Page 1. Influence of ionizing radiation and hot carrier injection on metal-oxide-semiconductor transistors This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2008 J. Phys. D: Appl. Phys. 41 023001 ...
Journal of Physics D Applied Physics, Oct 29, 2008
Experimentally measured electrical breakdown time delay data versus the afterglow period (represe... more Experimentally measured electrical breakdown time delay data versus the afterglow period (representing ‘memory curves’) for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar have been shown. The influence of N(4S) nitrogen atoms on secondary electron emission from the cathode (the SEE process) in late afterglow has been discussed. N(4S) atom concentration decay over relaxation time τ, N(4S)(τ), has been analysed by a numerical model and two analytical models. N(4S) decay analytical models are combined with different yield models that describe the SEE process by N(4S) and these combinations are employed to fit the experimental data. It has been shown that in late afterglow solving of very simple analytical equations instead of numerical solving of partial differential equations for N(4S)(τ) fitting can be used and that the combination of the first and the second order of the SEE process by N(4S) in yield modelling should be used in the case of 13.3 mbar pressure.
Advances in Clinical and Experimental Medicine, 2015
Background. Microwaves from mobile phones are one of the environmental toxicants that are capable... more Background. Microwaves from mobile phones are one of the environmental toxicants that are capable of compromising male fertility by inducing oxidative stress and apoptosis in the testes. Melatonin is a lipophilic tryptophan indole amine and a potent antioxidant. Objectives. The aim of the study was to evaluate the effect of melatonin treatment on oxidative stress parameters and DNA fragmentation in the testicular tissue of rats exposed to microwave radiation (4 h/day). Material and Methods. Adult Wistar rats were divided in 4 groups: I -treated with saline; II -treated with melatonin; III -exposed to microwaves; IV -exposed to microwaves and treated with melatonin. The melatonin (2 mg/kg ip) was administered daily. The animals were sacrificed after 20, 40 and 60 days. Results. Melatonin treatment prevented previously registered increases in malondialdehyde after only 20 days. Furthermore, it reversed the effects of microwave exposure on xanthine oxidase (after 40 days) and acid-DNase activity (after 20 days). However, neither protein carbonyl content nor catalase and alkaline Dnase activity were changed due to melatonin treatment. Conclusions. Melatonin exerts potent antioxidant effects in the testes of rats exposed to microwaves by decreasing the intensity of oxidative stress; it also reduces DNA fragmentation (Adv Clin Exp Med 2015, 24, 3, 429-436).
2015 IEEE 18th International Symposium on Design and Diagnostics of Electronic Circuits & Systems, 2015
ABSTRACT A single event latchup protection switch (SPS) has been developed in the IHP 250 nm bulk... more ABSTRACT A single event latchup protection switch (SPS) has been developed in the IHP 250 nm bulk CMOS technology. The SPS has been designed as a standard library cell intended for implementation in the radiation-tolerant application specific integrated circuits (ASICs). It provides detection of single event latchup and subsequent shutdown of power supply to critical elements within the chip to restore the normal operation. However, the SPS cell might be also susceptible to single event transients. In that regard, this work presents the simulation-based analysis of the response of SPS cell in the case of single event transients. The dependence of the single event transient response with respect to the injected charge, supply voltage, load and sensing transistor's size has been analyzed.
Proceedings of International Conference on Microelectronics, 1995
The behaviour of commercial n-channel power VDMOSFETs during γ-ray irradiation and subsequent ann... more The behaviour of commercial n-channel power VDMOSFETs during γ-ray irradiation and subsequent annealing at elevated temperature is investigated. The creation of positive oxide-trap charge dominates during irradiation, leading to negative threshold voltage shift. So called `latent' interface-trap buildup, observed during annealing after initial apparent saturation of interface-trap density, is identified as the main contributor to the threshold voltage rebound. At
1995 International Semiconductor Conference. CAS '95 Proceedings, 1995
The behaviour of the threshold voltage in commercial n-channel power VDMOSFETs during biased ther... more The behaviour of the threshold voltage in commercial n-channel power VDMOSFETs during biased thermal annealing, following γ-ray radiation exposure, is investigated. It is found that `rebound' effect, observed in transistors irradiated and annealed with positive gate bias, is mainly due to the `latent' interface-trap generation. Possible mechanism for latent interface-trap buildup is proposed
This paper presents results of a study of post-irradiation behavior of commercial n-channel power... more This paper presents results of a study of post-irradiation behavior of commercial n-channel power VDMOSFETs. Gamma-ray irradiated transistors have been subjected to the series of isothermal and isochronal annealings. The response of EFL1N10 devices, manufactured by domestic vendor, Ei-Microelectronics, is compared to that of Intersil's IRF510 devices. It has been found that during isothermal annealing EFL1N10 devices exhibit the so called latent interface-trap buildup (LITB), while such phenomenon hasn't been observed in IRF510. Additional switching temperature annealing and switching bias annealing experiments performed on EFL1N10 may prove useful in revealing details of LITB
The behavior of radiation-induced fixed traps (FTs) in gate oxide and radiation-induced switching... more The behavior of radiation-induced fixed traps (FTs) in gate oxide and radiation-induced switching traps (STs) near and at the gate oxide/substrate interface during irradiation up to high absorbed doses has been considered. The zero-bias voltage regime, the simplest and most popular solution in practice, was chosen. Indeed, it is very difficult to predict the creation of radiation defects in the case of low electric fields, because there is a compromise between the external low electric fields induced by work function differences and the internal electrical fields induced by radiation-induced charged defects in the oxide. It was shown that the density of FTs is higher than the density of STs for lower absorbed doses, though the trend is reversed for doses greater than 700Gy. Although the number of FTs is much higher than the number of STs, many FTs are located in the bulk, far from the oxide/semiconductor interface and their influence on channel carriers is much smaller than the influence of STs that are located closer to the channel. The equation for fitting the threshold voltage components induced by FTs (ΔVft) and by STs (ΔVst) is proposed and very good fittings are obtained. It is shown that five experimental irradiation points are sufficient to draw a good conclusion about the values of the fitting parameters, i.e., the voltage saturation values and the degree of linearity.
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Papers by Goran Ristic