Surface sensitivity of secondary electrons emitted from amorphous solids: Calculation of mean escape depth by a Monte Carlo method

2016 ◽  
Vol 120 (23) ◽  
pp. 235102 ◽  
Author(s):  
Y. B. Zou ◽  
S. F. Mao ◽  
B. Da ◽  
Z. J. Ding
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Amorphous Solids ◽  
Secondary Electrons ◽  
Surface Sensitivity ◽  
Escape Depth ◽  
Mean Escape Depth

A Simple Reverse Monte Carlo Algorithm for Structure Simulation of Multi-Component Amorphous Solids

1997 ◽  
Vol 11 (24) ◽  
pp. 1047-1055 ◽  
Author(s):  
M. Andrecut
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Amorphous Solids ◽  
Monte Carlo Algorithm ◽  
Reverse Monte Carlo ◽  
Structure Simulation ◽  
Reverse Monte Carlo Method

A simple Reverse Monte Carlo algorithm for structure simulations of multi-component amorphous solids is presented. The described algorithm is based on the standard reverse Monte Carlo method,1,2 developed for the monoatomic case, the application for poliatomic case being assured by using the Warren–Krutter–Morningstar approximation.3 An application for metal-metalloid glasses is also presented.

Measurements of the range of secondary electrons in low-Z materials

1984 ◽  
Vol 42 ◽  
pp. 356-357
Author(s):  
A. Muray ◽  
M. Isaacson ◽  
E. Kirkland
Keyword(s):  
Monte Carlo ◽  
Sample Surface ◽  
Mean Free Path ◽  
Simple Analytical Model ◽  
Si Substrate ◽  
Secondary Electrons ◽  
Monte Carlo Calculations ◽  
Escape Depth ◽  
Small Probe ◽  
Pattern Size

Previously, calculations of the resolution of SEM secondary electron images due to the escape depth of these electrons utilized Monte-Carlo calculations to simulate the “edge brightness effects” seen in high resolution magnification images obtained with small probe sizes (e.g.,). Similar Monte-Carlo calculations have been made to try to deduce the energy dissipation profiles in PMMA due to secondary electrons. We are trying to develop a simple analytical model which might allow us to get a better feel for the salient features with which the secondary electrons limit the pattern size in microfabrication and spatial resolution in the SEM.For our initial measurements, we have fabricated the structure shown in figure 1. The thickness of both the PMMA and Si substrate are less than one mean free path for inelastic scattering (of 100 keV electrons) thick. A 10 Å diameter beam of convergence angle of 15 mrad is incident normal to the sample surface.

Mean escape depth of secondary electrons emitted from semiconductors and insulators

2013 ◽  
Vol 87 (11) ◽  
pp. 1093-1097 ◽  
Author(s):  
A. G. Xie ◽  
S. R. Xiao ◽  
H. Y. Wu
Keyword(s):  
Secondary Electrons ◽  
Escape Depth ◽  
Mean Escape Depth

Distribution spatiale de la charge déposée dans des cibles minces irradiées par des électrons

1999 ◽  
Vol 77 (2) ◽  
pp. 127-136 ◽  
Author(s):  
F Alouani Bibi ◽  
V T Lazurik ◽  
Y V Rogov
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Atomic Number ◽  
Model Parameters ◽  
Secondary Electrons ◽  
Fast Electrons ◽  
Distribution Spatiale ◽  
Deposition Density ◽  
Charge Deposition ◽  
Computation Codes

The study of the charge-deposition distribution due to secondary electrons in thin slabs irradiated by fast electrons is conducted. The slabs considered have thicknesses from 0.5 to 50 mg/cm2 and are made of materials with atomic numbers from 4 to 79. The energy of incident electrons is considered from 1 to 10 MeV. The data of charge-deposition density are obtained by using a new Monte Carlo method called the trajectory translation method. An analysis of charge-deposition distribution and its dependencies on the energy of incident electrons and on the atomic number of the slab material and its thickness has been made. Conclusions concerning these dependencies and recommendations for the choice of the model parameters of the standard computation codes are provided.

Formulae for maximum yield and mean escape depth of secondary electrons emitted from metals

2017 ◽  
Vol 31 (26) ◽  
pp. 1750239 ◽  
Author(s):  
Ai-Gen Xie ◽  
Yu-Qing Xia ◽  
Xing Wang ◽  
Hao-Yu Liu ◽  
Shi Cheng
Keyword(s):  
Secondary Electron ◽  
Maximum Yield ◽  
Secondary Electron Emission ◽  
Average Energy ◽  
Primary Energy ◽  
Atomic Weight ◽  
Escape Probability ◽  
Secondary Electrons ◽  
Escape Depth ◽  
Mean Escape Depth

Based on the characteristics of secondary electron emission, the former formulae for the maximum yield of metals [Formula: see text] and primary range in the energy range of [Formula: see text] eV, relation [Formula: see text] among secondary electron escape probability [Formula: see text], average energy required to produce an internal secondary electron [Formula: see text], [Formula: see text], primary energy of [Formula: see text] ([Formula: see text] and parameter [Formula: see text] was deduced. On the basis of [Formula: see text] and the former formula for [Formula: see text], relation [Formula: see text] among mean escape depth of secondary electrons emitted from metals [Formula: see text], atomic number [Formula: see text], back-scattering coefficient [Formula: see text], material density [Formula: see text], [Formula: see text], atomic weight [Formula: see text] and [Formula: see text] was deduced. According to the deduced [Formula: see text], the formula for the ratio of [Formula: see text] to [Formula: see text] and experimental ratio of [Formula: see text] to [Formula: see text], relation [Formula: see text] among [Formula: see text], original work function [Formula: see text] and [Formula: see text] were empirically obtained. According to the characteristics of metal surface, [Formula: see text], [Formula: see text] and [Formula: see text], the formula for [Formula: see text] as a function of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] and that for [Formula: see text] as a function of [Formula: see text], [Formula: see text] and [Formula: see text] were deduced, respectively. The influences of surface change on [Formula: see text] and [Formula: see text] were analyzed. Calculated [Formula: see text] and [Formula: see text] were compared with the corresponding experimental ones. It was concluded that the deduced formulae for [Formula: see text] and [Formula: see text] can be used to estimate [Formula: see text] and [Formula: see text], respectively.

Outbursts of comet Schwassmann-Wachmann 1, and the cloud of interplanetary boulders

1974 ◽  
Vol 22 ◽  
pp. 307 ◽  
Author(s):  
Zdenek Sekanina
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Interplanetary Space ◽  
Porous Matrix ◽  
Maximum Diameter ◽  
Expansion Velocity ◽  
Solid Constituent ◽  
Meteoric Material ◽  
Periodic Comet

AbstractIt is suggested that the outbursts of Periodic Comet Schwassmann-Wachmann 1 are triggered by impacts of interplanetary boulders on the surface of the comet’s nucleus. The existence of a cloud of such boulders in interplanetary space was predicted by Harwit (1967). We have used the hypothesis to calculate the characteristics of the outbursts – such as their mean rate, optically important dimensions of ejected debris, expansion velocity of the ejecta, maximum diameter of the expanding cloud before it fades out, and the magnitude of the accompanying orbital impulse – and found them reasonably consistent with observations, if the solid constituent of the comet is assumed in the form of a porous matrix of lowstrength meteoric material. A Monte Carlo method was applied to simulate the distributions of impacts, their directions and impact velocities.

Structures and crystallization of vacuum-deposited amorphous Se and Sb films

1990 ◽  
Vol 48 (4) ◽  
pp. 140-141
Author(s):  
Makoto Shiojiri ◽  
Toshiyuki Isshiki ◽  
Tetsuya Fudaba ◽  
Yoshihiro Hirota
Keyword(s):  
Monte Carlo ◽  
Electron Microscope ◽  
Monte Carlo Method ◽  
Computer Program ◽  
Radial Distribution ◽  
Film Formation ◽  
Amorphous State ◽  
Two Dimensional ◽  
Amorphous Films ◽  
Binding Condition

In hexagonal Se crystal each atom is covalently bound to two others to form an endless spiral chain, and in Sb crystal each atom to three others to form an extended puckered sheet. Such chains and sheets may be regarded as one- and two- dimensional molecules, respectively. In this paper we investigate the structures in amorphous state of these elements and the crystallization.HRTEM and ED images of vacuum-deposited amorphous Se and Sb films were taken with a JEM-200CX electron microscope (Cs=1.2 mm). The structure models of amorphous films were constructed on a computer by Monte Carlo method. Generated atoms were subsequently deposited on a space of 2 nm×2 nm as they fulfiled the binding condition, to form a film 5 nm thick (Fig. 1a-1c). An improvement on a previous computer program has been made as to realize the actual film formation. Radial distribution fuction (RDF) curves, ED intensities and HRTEM images for the constructed structure models were calculated, and compared with the observed ones.

Imaging magnetic microstructure with SEMPA

1993 ◽  
Vol 51 ◽  
pp. 1032-1033
Author(s):  
M. H. Kelley ◽  
J. Unguris ◽  
R. J. Celotta ◽  
D. T. Pierce
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Sandwich Structure ◽  
Magnetic Coupling ◽  
Polarization Analysis ◽  
Secondary Electrons ◽  
Magnetic Microstructure ◽  
Escape Depth ◽  
Scanning Electron

By measuring the spin polarization of secondary electrons generated in a scanning electron microscope, scanning electron microscopy with polarization analysis (SEMPA) can directly image the magnitude and direction of a material’s magnetization. Because the escape depth of the secondaries is only on the order of 1 nm, SEMPA is especially well-suited for investigating the magnetization of ultra-thin films and surfaces. We have exploited this feature of SEMPA to study the magnetic microstrcture and magnetic coupling in ferromagnetic multilayers where the layers may only be a few atomic layers thick. For example, we have measured the magnetic coupling in Fe/Cr/Fe(100) and Fe/Ag/Fe(100) trilayers and have found that the coupling oscillates between ferromagnetic and antiferromagnetic as a function of the Cr or Ag spacer thickness.The SEMPA apparatus has been described in detail elsewhere. The sample consisted of a magnetic sandwich structure with a wedge-shaped interlayer as shown in Fig. 1.

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