Dependence of Reliability of Ultrathin Mos Gate Oxides on the Fermi Level Positions at Gate and Substrate

1997 ◽  
Vol 473 ◽  
Author(s):  
Tien-Chun Yang ◽  
Navakanta Bhat ◽  
Krishna C. Saraswat
Keyword(s):  
Electric Field ◽  
Fermi Level ◽  
Breakdown Strength ◽  
Gate Oxide ◽  
High Energy ◽  
Constant Current ◽  
Oxide Breakdown ◽  
Mos Devices ◽  
High Energy Electrons ◽  
Substrate Doping

ABSTRACTWe demonstrate that the reliability of ultrathin (< 10 nm) gate oxide in MOS devices depends on the Fermi level position at the gate, and not on the position at the substrate for constant current gate injection (Vg-). The oxide breakdown strength (Qbd) is less for p+ poly-Si gate than for n+ poly-Si gate, but, it is independent of the substrate doping type. The degradation of oxides is closely related to the electric field across the gate oxide, which is influenced by the cathode Fermi level. P+ poly-Si gate has higher barrier height for tunneled electrons, therefore, the cathode electric field must be higher to give the same injection current density. A higher electric field gives more high energy electrons at the anode, and therefore the damage is more at the substrate interface. Different substrate types cause no effect on the oxide electric field, and as a result, they do not influence the degradation.

Effect of Growth Conditions on the Reliability of Ultrathin MOS Gate Oxides

1996 ◽  
Vol 428 ◽  
Author(s):  
Tien-Chun Yang ◽  
Krishna C. Saraswat
Keyword(s):  
Gate Oxide ◽  
Interface State ◽  
Growth Conditions ◽  
Physical Stress ◽  
Constant Current ◽  
Strong Function ◽  
Oxidation Rates ◽  
Mos Devices ◽  
State Generation ◽  
Mos Gate

AbstractIn this work we demonstrate that in MOS devices the reliability of ultrathin (< 100Å) gate oxide is a strong function of growth conditions, such as, temperature and the growth rate. In addition, for constant current gate injection the degradation of SiO2 is enhanced as the thickness is reduced. We attribute this to physical stress in SiO2 resulting from the growth process. The degradation is always more for those growth conditions which result in higher physical stress in SiO2. Higher temperatures and slower oxidation rates allow stress relaxation through viscous flow and hence result in SiO2 of better reliability. We also found that for constant current stressing, the interface damage is more at the collecting electrode than at the injecting electrode. ΔDit (stress induced interface state generation) can be reduced after a high temperature Ar post anneal after the gate oxide growth.

scholarly journals Fast magnetic energy dissipation in relativistic plasma induced by high order laser modes

2016 ◽  
Vol 4 ◽  
Author(s):  
Y. J. Gu ◽  
Q. Yu ◽  
O. Klimo ◽  
T. Zh. Esirkepov ◽  
S. V. Bulanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Magnetic Energy ◽  
Collisionless Plasma ◽  
High Energy ◽  
Field Energy ◽  
Displacement Current ◽  
Particle In Cell ◽  
Magnetic Field Energy ◽  
High Energy Electrons

Fast magnetic field annihilation in a collisionless plasma is induced by using TEM(1,0) laser pulse. The magnetic quadrupole structure formation, expansion and annihilation stages are demonstrated with 2.5-dimensional particle-in-cell simulations. The magnetic field energy is converted to the electric field and accelerate the particles inside the annihilation plane. A bunch of high energy electrons moving backwards is detected in the current sheet. The strong displacement current is the dominant contribution which induces the longitudinal inductive electric field.

Characteristics of Post-Nitridation Rapid-Thermal Annealed Gate Oxide Grown on 4H-SiC

2005 ◽  
Vol 483-485 ◽  
pp. 689-692 ◽  
Author(s):  
K.Y. Cheong ◽  
Wook Bahng ◽  
Nam Kyun Kim
Keyword(s):  
Nitrous Oxide ◽  
Breakdown Strength ◽  
Gate Oxide ◽  
Electron Trapping ◽  
Interface Trap Density ◽  
Interface Trap ◽  
Oxide Charge ◽  
Oxide Breakdown ◽  
First Time ◽  
Electron Trapping Center

In this paper, the electrical properties of pre- and post-rapid thermal annealed 4H SiC-based gate oxide grown in 10% nitrous oxide (N2O) and in dry oxygen have been investigated, compared, and reported for the first time. After treating the nitrided gate oxide in rapid thermal annealing (RTA), oxide breakdown characteristic has been improved significantly. This improvement has been attributed to the reduction of SiC–SiO2 interface-trap density and the generation of positive oxide charge, acting as an electron-trapping center. However, deleterious effects have been observed in non-nitrided oxide after subjected to the same RTA treatment. The differences in oxide-breakdown strength of these oxides have been explained and modeled.

Accelerated Breakdown in Thin Oxide Films Due to Interfacial Stress and Carrier Depletion

1996 ◽  
Vol 428 ◽  
Author(s):  
V. Subramanian ◽  
N. Bhat ◽  
K. Saraswat
Keyword(s):  
Cathode Surface ◽  
Oxide Films ◽  
High Energy ◽  
Interfacial Stress ◽  
Constant Current ◽  
Current Stressing ◽  
Oxide Reliability ◽  
High Energy Electrons ◽  
Thin Oxide Films ◽  
Early Failures

AbstractWe present the results of experiments studying the effect of carrier depletion and interfacial stress on time to breakdown of'thin oxide films during constant current stressing High energy electrons resulting from carrier depletion conditions increase damage to oxides during tunneling. Carrier depletion conditions cause a dramatic decrease in time to breakdown and increase the number of early failures substantially. Mechanical interfacial stress results in a degradation in oxide reliability. Anode interfacial stress has been uniquely isolated from other phenomena such as cathode surface roughness, and has been shown to result in accelerated breakdown. These results have implications on oxide reliability and on test methodologies to obtain a measure of the same

Weak Violation of Electroneutrality in the Heliogeospheres: Electroneutrality Disorders

2020 ◽  
pp. 88-106 ◽  
Author(s):  
P.I. Vysikaylo
Keyword(s):  
Electric Field ◽  
Particle Density ◽  
Ionic Composition ◽  
High Energy ◽  
Alpha Particles ◽  
The Sun ◽  
Positive Ions ◽  
Debye Shielding ◽  
High Energy Electrons ◽  
Positively Charged

We prove that the occurrence of constant fluxes of positive ions with a large ratio of the charge number (Z) to the mass number of the ion (M) --- Z/M in the solar wind (SW) is due to an insignificant violation of the electroneutrality of the Sun and the entire heliosphere, the absence of Debye shielding of the solar charge due to due to the presence of a constant flux (current) of high-energy electrons from the Sun throughout the heliosphere and the appearance for protons, alpha particles and other positive ions with a ratio Z/M ≥ 0.107, Coulomb mirrors that reflect and accelerate them reflecting and accelerating them from the Sun. For the first time, the effective charge (1.4 kC) and other parameters of a positively charged Sun, which make it possible to estimate the electric field strength (E/N) reduced to particle density (N), were calculated from the ionic composition of SW (according to the minimum Z/M positive ions observed in experiments). This model allowed us to estimate the electric field intensity (E/N) reduced to the density of particles N in the photosphere, chromosphere, corona of the Sun (E/N ≈ 27· 103 Td), heliosphere and to investigate the conditions necessary for reflection of various positively charged particles --- ions from the positively charged Sun

Instability of Critical Electric Field in Gate Oxide Film of Heavy Ion Irradiated SiC MOSFETs

2015 ◽  
Vol 821-823 ◽  
pp. 673-676 ◽  
Author(s):  
Manato Deki ◽  
Takahiro Makino ◽  
Kazutoshi Kojima ◽  
Takuro Tomita ◽  
Takeshi Ohshima
Keyword(s):  
Silicon Carbide ◽  
Energy Transfer ◽  
Oxide Film ◽  
Electric Field ◽  
Ion Irradiation ◽  
Source Region ◽  
Gate Oxide ◽  
Heavy Ion ◽  
Mos Capacitors ◽  
Oxide Breakdown

The critical electric field (Ecr) of the gate oxide in 4H-Silicon Carbide (SiC) MOSFETs was measured under inversion bias conditions with ion irradiation. The Linear Energy Transfer (LET) dependence of theEcrat which the gate oxide breakdown occurred in these MOSFETs was evaluated. The linear relationship between theEcr-1andLETwas observed for SiC MOSFETs. The slope of theLET-1/Ecrfor SiC MOSFETs is almost the same that of theLET-1/Ecrlines for SiC MOS capacitors. TheVdsdependence ofEcrwas also evaluated. The correlation between the direction of electric field of drain-source region and direction of ion incidence affects to instability ofEcr.

A confident source of hard X-rays: radiation from a tokamak applicable for runaway electrons diagnosis

2016 ◽  
Vol 23 (5) ◽  
pp. 1227-1231 ◽  
Author(s):  
M. Kafi ◽  
A. Salar Elahi ◽  
M. Ghoranneviss ◽  
M. R. Ghanbari ◽  
M. K. Salem
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
High Energy ◽  
Toroidal Magnetic Field ◽  
Vacuum Vessel ◽  
X Rays ◽  
Runaway Electrons ◽  
High Energy Electrons ◽  
High Loop ◽  
The Mean

In a tokamak with a toroidal electric field, electrons that exceed the critical velocity are freely accelerated and can reach very high energies. These so-called `runaway electrons' can cause severe damage to the vacuum vessel and are a dangerous source of hard X-rays. Here the effect of toroidal electric and magnetic field changes on the characteristics of runaway electrons is reported. A possible technique for runaways diagnosis is the detection of hard X-ray radiation; for this purpose, a scintillator (NaI) was used. Because of the high loop voltage at the beginning of a plasma, this investigation was carried out on toroidal electric field changes in the first 5 ms interval from the beginning of the plasma. In addition, the toroidal magnetic field was monitored for the whole discharge time. The results indicate that with increasing toroidal electric field the mean energy of runaway electrons rises, and also an increase in the toroidal magnetic field can result in a decrease in intensity of magnetohydrodynamic oscillations which means that for both conditions more of these high-energy electrons will be generated.

scholarly journals Improved Breakdown Strength of Polypropylene Film by Polycyclic Compounds Addition for Power Capacitors

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1185
Author(s):  
Ranran Xu ◽  
Jiwen Xing ◽  
Boxue Du ◽  
Meng Xiao ◽  
Jin Li
Keyword(s):  
Original Film ◽  
Breakdown Strength ◽  
High Energy ◽  
Dc Conductivity ◽  
Electrical Performance ◽  
High Electron ◽  
Polycyclic Compounds ◽  
High Energy Electrons ◽  
High Electron Affinity ◽  
Chemistry Calculation

In this paper, an improved method for the electric performance of polypropylene (PP) film was proposed to promote the safety and stability of power capacitors. Modified PP films containing three different polycyclic compounds were prepared, which showed good thermal properties and decreased DC conductivity. The DC breakdown strength of the modified PP films under both positive and negative voltage is increased compared with that of the original film. The deep traps introduced by polycyclic compounds and the decreased carrier mobility give an explanation of the decreased DC conductivity. A quantum chemistry calculation was further performed to clarify the mechanism for improving electrical performance, presenting that polycyclic compounds with a high electron affinity and low ionization energy can capture high-energy electrons, protecting the PP molecular chain from attack, and then increase the breakdown strength. It is concluded that the modified PP films by polycyclic compounds have great potential in improving the insulating properties of power capacitors.

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