Numerical Calculation of Sub-Micron Hot Spot in Si Devices

2003 ◽  
Author(s):  
Kazuyoshi Fushinobu ◽  
Hirohisa Maruyama
Keyword(s):  
Numerical Calculation ◽  
Electron Temperature ◽  
Electron Concentration ◽  
Hot Spot ◽  
Lattice Temperature ◽  
Device Modeling ◽  
Electrical Behavior

Numerical calculation of silicon MOSFET is performed. Conjugate nature of the thermal and electrical behavior in the device is considered, and the lattice temperatures is solved as well as the electron concentration and the electron temperature. The calculated results shows the importance of considering both the electron and lattice temperatures for device modeling; the electron temperature has a significant impact on the calculated electron concentration and the lattice temperature. Submicron local hot spot is observed in the device, and its characteristics are discussed.

scholarly journals The Temperature Structure of NGC 7027

1989 ◽  
Vol 131 ◽  
pp. 176-176
Author(s):  
C. T. Daub ◽  
J. P. Basart
Keyword(s):  
Temperature Distribution ◽  
Electron Temperature ◽  
Angular Resolution ◽  
Hot Spot ◽  
Emission Measure ◽  
The Other ◽  
Radio Continuum ◽  
Line Of Sight ◽  
Temperature Structure ◽  
Ngc 7027

Radio maps of the free-free radio continuum flux (angular resolution ≅ 1.3 arcseconds) from NGC 7027 were made with the VLA operating at 20-cm, 6-cm, and 2-cm wavelengths which are near and straddle unit optical depth. Mean line-of-sight electron temperature and emission measure distributions were calculated by pairing the 2-cm and 6-cm maps, and the electron temperature distribution on the near side of the nebula was then obtained from the 20-cm map. The results suggest that the energy balance is complex in this planetary. For example, mean line-of-sight temperatures are higher than average in the direction of one of the bright lobes but not in the direction of the other. Especially noteworthy is an apparent “hot spot” on the near side of the nebula which has no apparent relation to either of the bright lobes, but it is approximately coincident with the brightest portion of the optical image.

scholarly journals Параметры микроканальной структуры в начальной фазе искрового разряда в воздухе атмосферного давления в промежутке острие-плоскость

2021 ◽  
Vol 47 (2) ◽  
pp. 24
Author(s):  
К.И. Алмазова ◽  
А.А. Амирова ◽  
А.Н. Белоногов ◽  
В.В. Боровков ◽  
Г.Б. Рагимханов ◽  
...  
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Electric Field ◽  
Electron Temperature ◽  
Electron Concentration ◽  
Initial Phase ◽  
Spark Discharge ◽  
Degree Of Ionization ◽  
Average Electron ◽  
High Degree

The results of investigations of the microstructure in the initial phase of a spark discharge in air in the 1.5 mm long gap between a tip and a plane are presented. Measurements show that, within 15 ns after breakdown, the channel is a set of a large number of microchannels, the current in the channel grows almost linearly up to 1 kA, and the electron concentration reaches the value of 2 • 10^19 cm^(−3). Kinetic processes in a separate microchannel were calculated based on the experimental data. It was found that the average electron temperature is in the range of 4-8 eV, the electric field is ~ 300 kV/cm, and the electrical conductivity is ∼10 Ω^(−1)•cm^(−1). The obtained results indicate that it is just the microstructure of the discharge determines the relatively high values of the average electron temperature in combination with a sufficiently high degree of ionization.

The Analysis of the Extrapolation Method Used in Typical Structures of Jacket Platforms

2015 ◽  
Author(s):  
Yifei Zhu ◽  
Shixiao Fu ◽  
Jianqiao Wu
Keyword(s):  
Numerical Calculation ◽  
Hot Spot ◽  
Shell Element ◽  
Welding Seam ◽  
Hot Spot Stress ◽  
Shell Elements ◽  
Tubular Joints ◽  
Element Simulation ◽  
Calculation Results ◽  
Fitting In

Acquiring the hot spot stress (HSS) in dangerous points of the structure (normally the welding seams of the structure) is the foundation of the offshore platform fatigue strength design. Because of the fact that it is very difficult and unpractical to install sensors in the welding seams, the most widely used method of acquiring the HSS currently is extrapolation, a method that obtains the HSS by extrapolating from stress of distant points. In order to figure out the feasibility of the method of extrapolation as well as the best ways to implement extrapolation in real practice, it is important to carry out numerical calculation of welded tubular joints in advance. To study the tubular joints, the finite element method (FEM) is the most widely adopted approach. In previous studies, shell elements are utilized to simulate tubular joints instead of solid elements concerning the difficulty. However, shell element simulation merely simulates the mid-surfaces of the tube walls so that shear stress in the direction of tube thicknesses are ignored, making the calculation of the stress concentration factor (SCF) inaccurate. In this study, the recommended ways of simulating the tubular Y- and T-joints are displayed and then the comparison of calculation results between different weld type, different mesh situations as well as different elements are given in order to bring up advice on numerical calculation for the study of extrapolation. The results of numerical calculation show that the extrapolation results are more accurate when we only consider the change of parameter α (chord length-to-chord radius ratio) and also, it is suggested to do the fitting in the area of 2t-4t away from the welding seam. These suggestions are verified by applying the method of extrapolation to a real jacket platform, which turns out that the fitting degree of extrapolation is very pleasant.

scholarly journals Piezoelectric interaction in controlling the effective electron temperature and the non-ohmic mobility characteristics in GaN and other III–V compounds at low lattice temperature

2017 ◽  
Vol 95 (2) ◽  
pp. 167-172 ◽  
Author(s):  
B. Das ◽  
A. Basu ◽  
J. Das ◽  
D.P. Bhattacharya
Keyword(s):  
Electron Temperature ◽  
Electrical Transport ◽  
Lattice Temperature ◽  
Relative Importance ◽  
Free Electrons ◽  
Effective Electron ◽  
Field Dependent ◽  
Indium Compounds ◽  
Effective Electron Temperature ◽  
Electrical Nonlinearity

In a compound semiconductor that lacks inversion symmetry, the free electrons interact simultaneously with the piezoelectric and acoustic phonons. This combined interaction principally controls the electrical transport at low lattice temperatures. Again, at low temperatures, the electrons in some of the compounds may be significantly perturbed for comparatively low fields, say, even for a fraction of a Vcm−1 or so, which effectively seems to be high enough, and the material exhibits electrical nonlinearity. Such a perturbed ensemble then attains a field dependent effective electron temperature Te, which exceeds the lattice temperature TL. The relative importance of the piezoelectric interaction in controlling the field dependence of the effective electron temperature, and therefrom, the non-ohmic mobility characteristics have been analyzed here under the condition of low lattice temperature. The numerical results obtained for InSb, InAs, and GaN are studied in detail. When compared with the experiments, the results here seem to give the same qualitative picture with respect to the variation of the non-ohmic mobility with the electric field for the indium compounds. The results, being interesting, stimulate further work in the same field.

Faceted antiphase boundaries in GaAs grown on Ge

1987 ◽  
Vol 45 ◽  
pp. 314-315
Author(s):  
N.-H. Cho ◽  
S. McKernan ◽  
C.B. Carter ◽  
K. Wagner
Keyword(s):  
Cross Section ◽  
Atomic Resolution ◽  
Face Centered Cubic ◽  
Electrical Behavior ◽  
Sphalerite Structure ◽  
Antiphase Boundaries ◽  
Transmission Electron ◽  
Face Centered ◽  
Quality Material ◽  
Simulated Images

Interest has recently increased in the possibility of growing III-V compounds epitactically on non-polar substrates to produce device quality material. Antiphase boundaries (APBs) may then develop in the GaAs epilayer because it has sphalerite structure (face-centered cubic with a two-atom basis). This planar defect may then influence the electrical behavior of the GaAs epilayer. The orientation of APBs and their propagation into GaAs epilayers have been investigated experimentally using both flat-on and cross-section transmission electron microscope techniques. APBs parallel to (110) plane have been viewed at the atomic resolution and compared to simulated images.Antiphase boundaries were observed in GaAs epilayers grown on (001) Ge substrates. In the image shown in Fig.1, which was obtained from a flat-on sample, the (110) APB planes can be seen end-on; the faceted APB is visible because of the stacking fault-like fringes arising from a lattice translation at this interface.

Sign in / Sign up

Export Citation Format

Share Document