In this paper, we report the results of consecutive irradiation and negative bias temperature (NBT) stress experiments performed on p-channel power vertical double-diffused metal-oxide semiconductor ...transistors. The purpose is to examine the effects of a specific kind of stress in devices previously subjected to the other kind of stress, as well as to assess if possible the behavior of devices subjected to simultaneous irradiation and NBT stressing. It is shown that irradiation of previously NBT stressed devices leads to a further increase of negative threshold voltage shift due to additional build-up of both oxide trapped charge and interface traps. NBT stress effects in previously irradiated devices may, however, depend on gate bias applied during irradiation and on the total dose received: in the cases of low-dose irradiation or irradiation without gate bias, the subsequent NBT stress seems to lead to further device degradation, whereas in the cases of devices previously irradiated to high doses or with gate bias applied during irradiation, NBT stress seems to have a positive role since it practically anneals a part of radiation-induced degradation.
Contribution: Impact assessment of the practice-oriented course for high school students on their later academic achievements, described in the context of long-term efforts to improve electronic ...engineering studies' quality. The article highlights the importance of outreach and extracurricular activities and cooperation with the IEEE in these efforts. Background: Faced with the practical application of theoretical knowledge, either in laboratory exercises or on small projects, students are not as successful as expected. A high school course promoting practical work has been developed, following the gathered experience and results from other studies. The intention was to track participants' progress not only on the course but also during their later studies at the faculty. Intended Outcomes: Increased the number of proficient high school students enrolling in the university. Improved quality of papers at student conferences, organization of workshops and events attractive to students and educators, an increased number of young members of the IEEE. Impact on the policymakers. Application Design: In tailoring the course content, the goal was to mimic an engineering design cycle through project-based learning. In contrast to deductive learning, which students were accustomed to, assessment-based and active learning teaching strategies, such as think-pair-share, practical demonstrations through performance tasks, and homework practice, have been used. Findings: This research documents that students with practical experience in high school have more self-confidence and better university scores than those with none. The universities should step forward in initiatives to strengthen connections with high schools and professional societies.
The behaviour of oxide and interface defects in n-channel power vertical
double-diffused metal-oxide-semiconductor field-effect transistors, firstly
degraded by the gamma-irradiation and electric ...field and subsequently
recovered and annealed, is presented. By analyzing the transfer
characteristic shifts, the changes of threshold voltage and underlying
changes of gate oxide and interface trap densities during the stress
(recovery, annealing) of investigated devices, it is shown that these two
types of stress influence differently on the gate oxide and the SiO2-Si
interface.
The annealing of radiation-induced defects in burn-in stressed n-channel
power VDMOSFETs with thick gate oxides (100 and 120 nm) is analysed. In
comparison with the previous spontaneous recovery, the ...changes of device
electrical parameters observed during annealing are highlighted by the
elevated temperature and voltage applied to the gate, and are more pronounced
in devices with a 120 nm thick gate oxide. The threshold voltage of VDMOSFETs
with a 100 nm thick gate oxide during annealing has an initially slow growth,
but then increases rapidly and reaches the value higher than the
pre-irradiation one (rebound effect). In the case of devices with a 120 nm
thick gate oxide, the threshold voltage behaviour also consists of a slight
initial increase followed by a rapid, but dilatory increase, with an obvious
tendency to achieve the rebound. The changes of channel carrier mobility
during annealing are similar in all samples: at first, it slowly and then
rapidly declines, and after reaching the minimum it begins to increase. In
the case of VDMOSFETs with a thicker gate oxide, these changes are much
slower. The underlying changes in the densities of gate oxide-trapped charge
and interface traps are also delayed in devices with a thicker gate oxide.
All these phenomena occur with certain delay in burn-in stressed devices
compared to unstressed ones. The leading role in the mechanisms responsible
for the observed phenomena is attributed to hydrogen related species.
U ovom radu analizirano je odzarivanje radijacionih defekata kod VDMOS
tranzistora snage sa ultradebelim oksidom gejta (100 nm i 120 nm), koji su
bili podvrgnuti temperaturno-naponskim testovima zarenja. U poredjenju sa
fazom spontanog oporavka prethodno ozracenih tranzistora, pokazano je da su
promene njihovih elektricnih parametara (napon praga i pokretljivosti
nosilaca) tokom odzarivanja prouzrokovane dejstvom povisene temperature i
napona na gejtu. Tokom odzarivanja VDMOS tranzistora snage sa oksidom gejta
debljine 100 nm, posle pocetnog laganog porasta, napon praga naglo pocinje da
raste dostizuci vrednost vecu od one pre ozracivanja. Kod tranzistora sa
oksidom gejta debljine 120 nm, napon praga takodje najpre lagano, a zatim
naglo (ali sa kasnjenjem) raste, sa ociglednom tendencijom da se ispolji
pomenuti skok napona praga. Promene pokretljivosti nosilaca tokom odzarivanja
su slicne kod obe grupe tranzistora: pokretljivost najpre lagano, a zatim
ostro opada, dostize minimum, a zatim pocinje da raste. U slucaju tranzistora
sa debljim oksidom gejta ove promene su znatno sporije. Odgovarajuce promene
gustina naelektrisanja u oksidu i povrsinskih stanja analizirane su sa
aspekta odgovornih mehanizama. Pokazano je da, kod tranzistora sa debljim
oksidom gejta, i promene gustina naelektrisanja u oksidu i povrsinskih stanja
takodje kasne. Svi pomenuti fenomeni tokom odzarivanja najpre su zapazeni kod
kontrolnih uzoraka, a zatim kod uzoraka koji su pre ozracivanja izlozeni
temperaturno-naponskim testovima zarenja. Kljucna uloga u pomenutim
mehanizmima pripisana je vodonikovim cesticama.
PR Projekat Ministarstva nauke Republike Srbije
This study aimed to comprehensively understand the performance and degradation of both p- and n-channel vertical double diffused MOS (VDMOS) transistors under bias temperature stress. Conducted ...experimental investigations involved various stress conditions and annealing processes to analyze the impacts of BT stress on the formation of oxide trapped charge and interface traps, leading to threshold voltage shifts. Findings revealed meaningful threshold voltage shifts in both PMOS and NMOS devices due to stresses, and the subsequent annealing process was analyzed in detail. The study also examined the influence of stress history on self-heating behavior under real operating conditions. Additionally, the study elucidated the complex correlation between stress-induced degradation and device reliability. The insights contribute to optimizing the performance and permanence of VDMOS transistors in practical applications, advancing semiconductor technology. This study underscored the importance of considering stress-induced effects on device reliability and performance in the design and application of VDMOS transistors.
Our recent research of the effects of pulsed bias NBT stressing in p-channel
power VDMOSFETs is reviewed in this paper. The reduced degradation normally
observed under the pulsed stress bias ...conditions is discussed in terms of the
dynamic recovery effects, which are further assessed by varying the duty
cycle ratio and frequency of the pulsed stress voltage. The results are
analyzed in terms of the effects on device lifetime as well. A tendency of
stress induced degradation to decrease with lowering the duty cycle and/or
increasing the frequency of the pulsed stress voltage, which leads to the
increase in device lifetime, is explained in terms of enhanced dynamic
recovery effects.
This paper gives insight on the WebSocket communication method in Internet of Things system, where the hardware part of the system is based on ESP32 microcontroller. Method of implementation is ...discussed and the reliability of the real-time data transfer in Wi-Fi networks is tested and compared with the long-polling method. Special circuit is designed with the goal to stress the hardware part of the system and the client-server communication link in order to enable proper comparison of data transfer methods. For the comprehensive testing of the real-time data ow, a web server application is designed and used to visualize received data. Impact of RSSI on transfer methods is discussed as well. Eciency of the WebSocket method is discussed and then compared to the long-polling method.
This paper presents the bibliographic review of smart systems implemented so
far and their application. Also this paper is dedicated to new smart mobile
system developed for monitoring microclimatic ...parameters. This system is
primarily intended for monitoring real-time microclimatic parameters, such
as air quality where the presence of carbon monoxide (CO) is monitored, as
well as other microclimatic parameters. The mobile system which will be
described in this manuscript can be installed in public transport (to obtain
information on microclimatic parameters on a known route). Also, to obtain
information on microclimatic parameters from a random route, it is possible
to install the system in a taxi vehicle. This system provides the ability to
generate a map using the data provided by the system based on GPS
coordinates. The system is based on a group of embedded sensors, GPS module,
PIC microcontroller as a core and server system, and wireless internet using
Global System for Mobile Telecommunications (GSM) module with General Packet
Radio Service (GPRS) as a communication protocol.
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