scholarly journals Spice modeling of ionizing radiation effects in CMOS devices

2017 ◽  
Vol 30 (2) ◽  
pp. 161-178
Author(s):  
Tatjana Pesic-Brdjanin
Keyword(s):  
Ionizing Radiation ◽  
Surface Potential ◽  
Radiation Effects ◽  
Silicon Oxide ◽  
Gate Oxide ◽  
Time Dependent ◽  
Voltage Threshold ◽  
Mos Transistor ◽  
The Impact ◽  
Constant Shift

Electric characteristics of devices in advanced CMOS technologies change over the time because of the impact of the ionizing radiation effects. Device aging is caused by cumulative contribution of generation of defects in the gate oxide and/or at the interface silicon-oxide. The concentration of these defects is time and bias-dependent values. Existing models include these effects through constant shift of voltage threshold. A method for including ionizing radiation effects in Spice models of MOS transistor and FinFET, based on an auxiliary diode circuit using for derivation of values of surface potential, that also calculates the correction time-dependent voltage due to concentration of trapped charges, is shown in this paper.

On the Impact of Grown-in Silicon Oxide Precipitate Nuclei on Silicon Gate Oxide Integrity

1996 ◽  
pp. 493-500 ◽  
Author(s):  
J. Vanhellemont ◽  
G. Kissinger ◽  
K. Kenis ◽  
M. Depas ◽  
D. Gräf ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
Gate Oxide ◽  
The Impact ◽  
Oxide Precipitate ◽  
Gate Oxide Integrity

TOTAL-DOSE AND SINGLE-EVENT EFFECTS IN SILICON-GERMANIUM HETEROJUNCTION BIPOLAR TRANSISTORS

2004 ◽  
Vol 14 (02) ◽  
pp. 489-501
Author(s):  
JOHN D. CRESSLER
Keyword(s):  
Ionizing Radiation ◽  
Heterojunction Bipolar Transistors ◽  
Silicon Germanium ◽  
Radiation Effects ◽  
Bipolar Transistors ◽  
Electronic Systems ◽  
Single Event ◽  
Sige Hbt ◽  
Radiation Induced ◽  
The Impact

We present an overview of radiation effects in silicon-germanium heterojunction bipolar transistors ( SiGe HBT). We begin by reviewing SiGe HBTs, and then examine the impact of ionizing radiation on both the dc and ac performance of SiGe HBTs, the circuit-level impact of radiation-induced changes in the transistors, followed by single-event phenomena in SiGe HBT circuits. While ionizing radiation degrades both the dc and ac properties of SiGe HBTs, this degradation is remarkably minor, and is far better than that observed in even radiation-hardened conventional Si BJT technologies. This fact is particularly significant given that no intentional radiation hardening is needed to ensure this level of both device-level and circuit-level tolerance (typically multi-Mrad TID). SEU effects are pronounced in SiGe HBT circuits, as expected, but circuit-level mitigation schemes will likely be suitable to ensure adequate tolerance for many orbital missions. SiGe HBT technology thus offers many interesting possibilities for space-borne electronic systems.

The impact of statin therapy after surgical or endovascular treatment of cerebral aneurysms

2020 ◽  
Vol 133 (1) ◽  
pp. 182-189
Author(s):  
Tae-Jin Song ◽  
Seung-Hun Oh ◽  
Jinkwon Kim
Keyword(s):  
Statin Therapy ◽  
Coil Embolization ◽  
Primary Outcome ◽  
Cox Regression ◽  
Cerebral Aneurysms ◽  
Time Dependent ◽  
Lipid Lowering ◽  
Surgical Clipping ◽  
The Impact

OBJECTIVECerebral aneurysms represent the most common cause of spontaneous subarachnoid hemorrhage. Statins are lipid-lowering agents that may expert multiple pleiotropic vascular protective effects. The authors hypothesized that statin therapy after coil embolization or surgical clipping of cerebral aneurysms might improve clinical outcomes.METHODSThis was a retrospective cohort study using the National Health Insurance Service–National Sample Cohort Database in Korea. Patients who underwent coil embolization or surgical clipping for cerebral aneurysm between 2002 and 2013 were included. Based on prescription claims, the authors calculated the proportion of days covered (PDC) by statins during follow-up as a marker of statin therapy. The primary outcome was a composite of the development of stroke, myocardial infarction, and all-cause death. Multivariate time-dependent Cox regression analyses were performed.RESULTSA total of 1381 patients who underwent coil embolization (n = 542) or surgical clipping (n = 839) of cerebral aneurysms were included in this study. During the mean (± SD) follow-up period of 3.83 ± 3.35 years, 335 (24.3%) patients experienced the primary outcome. Adjustments were performed for sex, age (as a continuous variable), treatment modality, aneurysm rupture status (ruptured or unruptured aneurysm), hypertension, diabetes mellitus, household income level, and prior history of ischemic stroke or intracerebral hemorrhage as time-independent variables and statin therapy during follow-up as a time-dependent variable. Consistent statin therapy (PDC > 80%) was significantly associated with a lower risk of the primary outcome (adjusted hazard ratio 0.34, 95% CI 0.14–0.85).CONCLUSIONSConsistent statin therapy was significantly associated with better prognosis after coil embolization or surgical clipping of cerebral aneurysms.

An Analytical Modeling and Performance Analysis of Graded Work Function Gate Recessed Channel SOI-MOSFET

2019 ◽  
Vol 9 (4) ◽  
pp. 504-511
Author(s):  
Sikha Mishra ◽  
Urmila Bhanja ◽  
Guru Prasad Mishra
Keyword(s):  
Analytical Model ◽  
Surface Potential ◽  
Threshold Voltage ◽  
Silicon On Insulator ◽  
Junction Depth ◽  
Short Channel ◽  
Soi Mosfet ◽  
Minimum Surface ◽  
Recessed Channel ◽  
The Impact

Introduction: A new analytical model is designed for Workfunction Modulated Rectangular Recessed Channel-Silicon On Insulator (WMRRC-SOI) MOSFET that considers the concept of groove gate and implements an idea of workfunction engineering. Methods: The impact of Negative Junction Depth (NJD) and oxide thickness (tox) are analyzed on device performances such as Sub-threshold Slope (SS), Drain Induced Barrier Lowering (DIBL) and threshold voltage. Results: The results of the proposed work are evaluated with the Rectangular Recessed Channel-Silicon On Insulator (RRC-SOI) MOSFET keeping the metal workfunction constant throughout the gate region. Furthermore, an analytical model is developed using 2D Poisson’s equation and threshold voltage is estimated in terms of minimum surface potential. Conclusion: In this work, the impact of Negative Junction Depth (NJD) on minimum surface potential and the drain current are also evaluated. It is observed from the analysis that the analog switching performance of WMRRC-SOI MOSFET surpasses RRC-SOI MOSFET in terms of better driving capability, high Ion/Ioff ratio, minimized Short Channel Effects (SCEs) and hot carrier immunity. Results are simulated using 2D Sentaurus TCAD simulator for validation of the proposed structure.

COVID-19: Time-Dependent Effective Reproduction Number and Sub-notification Effect Estimation Modeling (Preprint)

2020 ◽  
Author(s):  
Eduardo Atem De Carvalho ◽  
Rogerio Atem De Carvalho
Keyword(s):  
New York ◽  
Reproduction Number ◽  
Moving Average ◽  
Real Data ◽  
Time Dependent ◽  
Initial Value ◽  
Health Authorities ◽  
Reproduction Numbers ◽  
Effect Estimation ◽  
The Impact

BACKGROUND Since the beginning of the COVID-19 pandemic, researchers and health authorities have sought to identify the different parameters that govern their infection and death cycles, in order to be able to make better decisions. In particular, a series of reproduction number estimation models have been presented, with different practical results. OBJECTIVE This article aims to present an effective and efficient model for estimating the Reproduction Number and to discuss the impacts of sub-notification on these calculations. METHODS The concept of Moving Average Method with Initial value (MAMI) is used, as well as a model for Rt, the Reproduction Number, is derived from experimental data. The models are applied to real data and their performance is presented. RESULTS Analyses on Rt and sub-notification effects for Germany, Italy, Sweden, United Kingdom, South Korea, and the State of New York are presented to show the performance of the methods here introduced. CONCLUSIONS We show that, with relatively simple mathematical tools, it is possible to obtain reliable values for time-dependent, incubation period-independent Reproduction Numbers (Rt). We also demonstrate that the impact of sub-notification is relatively low, after the initial phase of the epidemic cycle has passed.

Using a Temperature-Switching Approach to Evaluate Low-Dose-Rate Ionizing Radiation Effects on SET in Linear Bipolar Circuits

2019 ◽  
Vol 66 (7) ◽  
pp. 1557-1565 ◽  
Author(s):  
Shuai Yao ◽  
Wu Lu ◽  
Xin Yu ◽  
Qi Guo ◽  
Chengfa He ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Dose Rate ◽  
Radiation Effects ◽  
Low Dose ◽  
Low Dose Rate

Hydrogen Concentration Analysis in Pecvd and Rtcvd Silicon Nitride Thin Films and It's Impact on Device Performance

2001 ◽  
Vol 664 ◽  
Author(s):  
C. Y. Wang ◽  
E. H. Lim ◽  
H. Liu ◽  
J. L. Sudijono ◽  
T. C. Ang ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Threshold Voltage ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Gate Oxide ◽  
Nitride Film ◽  
Device Performance ◽  
Gas Flow Ratio ◽  
The Impact

ABSTRACTIn this paper the impact of the ESL (Etch Stop layer) nitride on the device performance especially the threshold voltage (Vt) has been studied. From SIMS analysis, it is found that different nitride gives different H concentration, [H] in the Gate oxide area, the higher [H] in the nitride film, the higher H in the Gate Oxide area and the lower the threshold voltage. It is also found that using TiSi instead of CoSi can help to stop the H from diffusing into Gate Oxide/channel area, resulting in a smaller threshold voltage drift for the device employed TiSi. Study to control the [H] in the nitride film is also carried out. In this paper, RBS, HFS and FTIR are used to analyze the composition changes of the SiN films prepared using Plasma enhanced Chemical Vapor deposition (PECVD), Rapid Thermal Chemical Vapor Deposition (RTCVD) with different process parameters. Gas flow ratio, RF power and temperature are found to be the key factors that affect the composition and the H concentration in the film. It is found that the nearer the SiN composition to stoichiometric Si3N4, the lower the [H] in SiN film because there is no excess silicon or nitrogen to be bonded with H. However the lowest [H] in the SiN film is limited by temperature. The higher the process temperature the lower the [H] can be obtained in the SiN film and the nearer the composition to stoichiometric Si3N4.

Effect of Technology Scaling on MOS Transistor Performance with High-K Gate Dielectrics

2002 ◽  
Vol 716 ◽  
Author(s):  
Nihar R. Mohapatra ◽  
Madhav P. Desai ◽  
Siva G. Narendra ◽  
V. Ramgopal Rao
Keyword(s):  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Channel Length ◽  
Mos Transistors ◽  
Short Channel ◽  
Technology Scaling ◽  
Mos Transistor ◽  
Wide Range ◽  
Impact Of Technology ◽  
The Impact

AbstractThe impact of technology scaling on the MOS transistor performance is studied over a wide range of dielectric permittivities using two-dimensional (2-D) device simulations. It is found that the device short channel performance is degraded with increase in the dielectric permittivity due to an increase in dielectric physical thickness to channel length ratio. For Kgate greater than Ksi, we observe a substantial coupling between source and drain regions through the gate dielectric. We provide extensive 2-D device simulation results to prove this point. Since much of the coupling between source and drain occurs through the gate dielectric, it is observed that the overlap length is an important parameter for optimizing DC performance in the short channel MOS transistors. The effect of stacked gate dielectric and spacer dielectric on the MOS transistor performance is also studied to substantiate the above observations.

Nitrogen Implantation and Diffusion in Silicon

1999 ◽  
Vol 568 ◽  
Author(s):  
Lahir Shaik Adam ◽  
Mark E. Law ◽  
Omer Dokumaci ◽  
Yaser Haddara ◽  
Cheruvu Murthy ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
Gate Oxide ◽  
Nitrogen Diffusion ◽  
Nitrogen Implantation ◽  
Oxide Interface ◽  
Diffusion Behavior ◽  
Czochralski Silicon ◽  
Interface Modeling ◽  
And Diffusion ◽  
Silicon Silicon

ABSTRACTNitrogen implantation can be used to control gate oxide thicknesses [1,2]. This study aims at studying the fundamental behavior of nitrogen diffusion in silicon. Nitrogen at sub-amorphizing doses has been implanted as N2+ at 40 keV and 200 keV into Czochralski silicon wafers. Furnace anneals have been performed at a range of temperatures from 650°C through 1050°C. The resulting annealed profiles show anomalous diffusion behavior. For the 40 keV implants, nitrogen diffuses very rapidly and segregates at the silicon/ silicon-oxide interface. Modeling of this behavior is based on the theory that the diffusion is limited by the time to create a mobile nitrogen interstitial.

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