Single-event-transient effect in nanotube tunnel field-effect transistor with bias-induced electron–hole bilayer

The single event transient(SET)effect in nanotube tunneling field-effect transistor with bias-induced electron–hole bilayer(EHBNT-TFET)is investigated by 3-D TCAD simulation for the first time.The effects of linear energy transfer(LET),characteristic radius,strike angle,electrode bias and hit location on SET response are evaluated in detail.The simulation results show that the peak value of transient drain current is up to 0.08 m A for heavy ion irradiation with characteristic radius of 50 nm and LET of 10 Me V·cm^(2)/mg,which is much higher than the on-state current of EHBNTTFET.The SET response of EHBNT-TFET presents an obvious dependence on LET,strike angle,drain bias and hit location.As LET increases from 2 Me V·cm^(2)/mg to 10 Me V·cm^(2)/mg,the peak drain current increases monotonically from 0.015 mA to 0.08 mA.The strike angle has an greater impact on peak drain current especially for the smaller characteristic radius.The peak drain current and collected charge increase by 0.014 mA and 0.06 fC,respectively,as the drain bias increases from 0.1 V to 0.9 V.Whether from the horizontal or the vertical direction,the most sensitive hit location is related to wt.The underlying physical mechanism is explored and discussed.

A single-event transient induced by a pulsed laser in a silicon-germanium heterojunction bipolar transistor

A study on the single event transient （SET） induced by a pulsed laser in a silicon-germanium （SiGe） heterojunction bipolar transistor （HBT） is presented in this work. The impacts of laser energy and collector load resistance on the SET are investigated in detail. The waveform, amplitude, and width of the SET pulse as well as collected charge are used to characterize the SET response. The experimental results are discussed in detail and it is demonstrated that the laser energy and load resistance significantly affect the SET in the SiGe HBT. Furthermore, the underlying physical mechanisms are analyzed and investigated, and a near-ideal exponential model is proposed for the first time to describe the discharge of laser-induced electrons via collector resistance to collector supply when both base-collector and collector-substrate junctions are reverse biased or weakly forward biased. Besides, it is found that an additional multi-path discharge would play an important role in the SET once the base-collector and collector-substrate junctions get strongly forward biased due to a strong transient step charge by the laser pulse.

Studies of reasonability of computing return period of storm surge based on random events set

In order to study whether the random events set can be used in Rudongbank of Nantong or not, we use ADCIRC model to stimulate the storm surge affectingRudong bank based on random events set. Then we use p-III curve to fit peak-value ofsurge of all the years to get the surge of typical return periods. The result shows that theresults of fitting by ADCIRC and by historical data coincide well in lower return periods,but to higher return periods, the results of fitting by ADCIRC are significantly higher thanthat of fitting by historical data. Due to the short time, it’s not enough for the extremestorm surge events to occur, the results of higher return periods are not reliable, so wecan’t rule out the reasonability of results based on random events set. The results offitting based on random events set are accurate in lower return periods and we can alsofully estimate the surge of higher return periods based on random events set. In thesituation of lacking historical data of hundreds of years, random events set can beaccepted as a tool to compute the return period of storm surge. Consideration of globalwarming, the possibility of super typhoons’ appearance will rise, which will result inhigher surge of return periods. In order to prevent the disaster of storm surge, thegovernment needs to deepen and reinforce the coastal engineering like seawalls and embankments.

The dual role of multiple-transistor charge sharing collection in single-event transients

As technologies scale down in size, multiple-transistors being affected by a single ion has become a universal phenomenon, and some new effects are present in single event transients （SETs） due to the charge sharing collection of the adjacent multiple-transistors. In this paper, not only the off-state p-channel metal–oxide semiconductor field-effect transistor （PMOS FET）, but also the on-state PMOS is struck by a heavy-ion in the two-transistor inverter chain, due to the charge sharing collection and the electrical interaction. The SET induced by striking the off-state PMOS is efficiently mitigated by the pulse quenching effect, but the SET induced by striking the on-state PMOS becomes dominant. It is indicated in this study that in the advanced technologies, the SET will no longer just be induced by an ion striking the off-state transistor, and the SET sensitive region will no longer just surround the off-state transistor either, as it is in the older technologies. We also discuss this issue in a three-transistor inverter in depth, and the study illustrates that the three-transistor inverter is still a better replacement for spaceborne integrated circuit design in advanced technologies.

Novel N-hit single event transient mitigation technique via open guard transistor in 65 nm bulk CMOS process

In this paper,we proposed a new n-channel MOS single event transient(SET) mitigation technique,which is called the open guard transistor(OGT) technique.This hardening scheme is compared with several classical n-channel MOS hardening structures through 3-D TCAD simulations.The results show that this scheme presents about 35% improvements over the unhardened scheme for mitigating the SET pulse,and its upgrade,the 2-fringe scheme,takes on even more than 50% improvements over the unhardened one.This makes significant sense for the semi-conductor device reliability.

Single event transient pulse attenuation effect in three-transistor inverter chain

In this paper, compared with two-transistor (2T) inverter chain, the production and propagation of P-hit single event transient (SET) in three-transistor (3T) inverter chain is studied in depth based on three-dimensional numerical simulations in a 90 nm bulk complementary metal oxide semiconductor (CMOS) technology. The pulse attenuation effect is found in 3T inverter chain, and the pulse can not completely propagate through the inverter chain as LET increases. The discovery will provide a new insight into SET hardened design, the 3T inverter layout structure (or similar layout structures) will be a better method in integrated circuits (ICs) design in radiation environment.

P-Tree Structures and Event Horizon： Efficient Event-Set Implementations

This paper describes efficient data structures, namely the Indexed P-tree, Block P-tree, and Indexed-Block P-tree （or/P-tree, BP-tree, and IBP-tree, respectively, for short）, for maintaining future events in a general purpose discrete event simulation system, and studies the performance of their event set algorithms under the event horizon principle. For comparison reasons, some well-known event set algorithms have been selected and studied, that is, the Dynamic-heap and the P-tree algorithms. To gain insight into the performance of the proposed event set algorithms and allow comparisons with the other selected algorithms, they are tested under a wide variety of conditions in an experimental way. The time needed for the execution of the Hold operation is taken as the measure for estimating the average time complexity of the algorithms. The experimental results show that the BP-tree algorithm and the IBP-tree algorithm behave very well with the event set of all the sizes and their performance is almost independent of the stochastic distributions.

Experimental characterization of the bipolar effect on P-hit single-event transients in 65 nm twin-well and triple-well CMOS technologies

Single-event charge collection is controlled by drift, diffusion and the bipolar effect. Previous work has established that the bipolar effect is significant in the p-type metal-oxide-semiconductor field-effect transistor(PMOS) in 90 nm technology and above. However, the consequences of the bipolar effect on P-hit single-event transients have still not completely been characterized in 65 nm technology. In this paper, characterization of the consequences of the bipolar effect on P-hit single-event transients is performed by heavy ion experiments in both 65 nm twin-well and triple-well complementary metal-oxide-semiconductor(CMOS) technologies. Two inverter chains with clever layout structures are explored for the characterization. Ge(linear energy transfer(LET) = 37.4 Me V cm^2/mg) and Ti(LET = 22.2 Me V cm^2/mg) particles are also employed. The experimental results show that with Ge(Ti) exposure, the average pulse reduction is 49 ps(45 ps) in triple-well CMOS technology and 42 ps(32 ps) in twin-well CMOS technology when the bipolar effect is efficiently mitigated. This characterization will provide an important reference for radiation hardening integrated circuit design.

Modeling to predict the time evolution of negative bias temperature instability(NBTI) induced single event transient pulse broadening

An analytical model is proposed to calculate single event transient (SET) pulse width with bulk complementary metal oxide semiconductor (CMOS) technology based on the physics of semiconductor devices. Combining with the most prevalent negative bias temperature instability (NBTI) degradation model, a novel analytical model is developed to predict the time evolution of the NBTI induced SET broadening in the production, and NBTI experiments and three-dimensional numerical device simulations are used to verify the model. At the same time, an analytical model to predict the time evolution of the NBTI induced SET broadening in the propagation is also proposed, and NBTI experiments and the simulation program with integrated circuit emphasis (SPICE) are used to verify the proposed model.

Making Meaning through Prepositions:A Model for Teacher Trainees

This paper proposes a cognitive-semiotic model for teaching English prepositions within teacher training programs.The model is presented as a three-session grammar module that involves 1)creating an environment for the learners to see prepositional polysemy as multiple ways of viewing Trajector(TR)-Landmark(LM)spatial configurations(Tyler&Evans,2003,2005)and 2)guiding them to make meaning through prepositions in the context of Radden and Dirven’s(2007)event schemas.This is a simplex to complex inventory of constructions for talking about world events(i.e.the material,psychological and force-dynamic world events)that can be presented as manipulations of a basic TR-LM spatial configuration.Such a module is useful for native and non-native English teacher trainees alike considering that it allows for covering prepositional polysemy and use in a systematically graded manner,a manner that may help teacher trainees to learn to prepare conceptually-linked,graded materials for teaching prepositions to EFL(English as a foreign language)learners.

A radiation-hardened-by-design technique for suppressing SET in charge pump of PLL frequency synthesizer

This paper presents a single event transient(SET) suppressor circuit,which can suppress the effect of SET in charge pump(CP) on the whole PLL frequency synthesizers,and at the same time it brings little negative effect to the system during normal operation.Because the proposed SET suppressor circuit only includes a resistor,a PMOS and an NMOS device,little area penalty is introduced.By preventing SET propagating from CP to low pass filter(LPF) and VCO when a single event strikes on CP output node,the system shows excellent hardness to SET in CP.Mixed simulations are performed on TCAD workbench.The results show that a single event with an LET at 80 MeV cm 2 /mg can only induce approximately 2.3 mV disturbance on the control voltage of VCO.