Prefiltration technique via aggregation for constructing low-density high-quality factorized sparse approximate inverse preconditionings

2003 ◽  
Vol 10 (3) ◽  
pp. 235-246 ◽  
Author(s):  
A. A. Nikishin ◽  
A. Yu. Yeremin
Keyword(s):  
Low Density ◽  
High Quality ◽  
Approximate Inverse ◽  
Sparse Approximate Inverse

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

Fundamental Study of the Temperature Ramp-Up Influence for 3C-SiC Hetero-Epitaxy on Silicon (100)

2010 ◽  
Vol 645-648 ◽  
pp. 151-154 ◽  
Author(s):  
Philip Hens ◽  
Günter Wagner ◽  
Astrid Hölzing ◽  
Rainer Hock ◽  
Peter J. Wellmann
Keyword(s):  
Nucleation Rate ◽  
Carbon Layer ◽  
Low Density ◽  
High Quality ◽  
Fundamental Study ◽  
Temperature Range ◽  
Peak Intensity ◽  
Temperature Ramp ◽  
Domain Boundaries

Usually a waiting step at around 1000°C to 1100°C during the carbonization step for 3C-SiC on silicon is implemented for establishing a closed carbon layer to prevent the formation of voids. The latter, however, may lead to non-ideal nucleation conditions for high quality layers with a low density of domain boundaries. Our investigations indicate that a continuous ramp-up as fast as possible with no waiting step would be preferable. The worst layer quality, as measured by peak intensity and FWHM of the (200) reflection of 3C SiC, can be found at a temperature of about 1000°C, which indicates that here the nucleation rate would be the highest. So longer periods within this temperature range should be avoided by applying high ramping speeds during the carbonization step.

An adaptive multilevel factorized sparse approximate inverse preconditioning

2017 ◽  
Vol 113 ◽  
pp. 19-24 ◽  
Author(s):  
Jiří Kopal ◽  
Miroslav Rozložník ◽  
Miroslav Tůma
Keyword(s):  
Approximate Inverse ◽  
Sparse Approximate Inverse

scholarly journals Application of Hierarchical Two-Level Spectral Preconditioning Method for Electromagnetic Scattering from the Rough Surface

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
D. Z. Ding ◽  
G. M. Li ◽  
Y. Y. An ◽  
R. S. Chen
Keyword(s):  
Rough Surface ◽  
Electromagnetic Scattering ◽  
Fast Multipole Method ◽  
Scattering Problems ◽  
Approximate Inverse ◽  
Sparse Approximate Inverse ◽  
Preconditioning Method ◽  
Speed Up ◽  
Spectral Preconditioner ◽  
Field Integral

The higher-order hierarchical Legendre basis functions combining the electrical field integral equations (EFIE) are developed to solve the scattering problems from the rough surface. The hierarchical two-level spectral preconditioning method is developed for the generalized minimal residual iterative method (GMRES). The hierarchical two-level spectral preconditioner is constructed by combining the spectral preconditioner and sparse approximate inverse (SAI) preconditioner to speed up the convergence rate of iterative methods. The multilevel fast multipole method (MLFMM) is employed to reduce memory requirement and computational complexity of the method of moments (MoM) solution. The accuracy and efficiency are confirmed with a couple of numerical examples.

A Dynamic Pattern Factored Sparse Approximate Inverse Preconditioner on Graphics Processing Units

2019 ◽  
Vol 41 (3) ◽  
pp. C139-C160 ◽  
Author(s):  
Massimo Bernaschi ◽  
Mauro Carrozzo ◽  
Andrea Franceschini ◽  
Carlo Janna
Keyword(s):  
Graphics Processing Units ◽  
Approximate Inverse ◽  
Dynamic Pattern ◽  
Sparse Approximate Inverse ◽  
Graphics Processing
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