Monte Carlo Simulation on the CD-SEM Images of SiO2/Si Systems

2019 ◽  
Vol 25 (4) ◽  
pp. 849-858
Author(s):  
P. Zhang

AbstractSilicon dioxide (SiO2) has been the most important insulator in the highly-developed field of silicon (Si) technology. Accurate pitch and gate linewidth measurements for SiO2/Si systems (systems with a SiO2 insulating layer and Si substrate) have become necessary. Studying one such system obviously presents different results from that of the widely researched Si/Si structure, because the edge profile of the secondary electron (SE) signal contains contributions from two materials. In this work, several scanning electron microscope (SEM) images and SE profiles of SiO2/Si pitch and trapezoidal line structures, using various geometric and experimental parameters, were simulated through the use of Monte Carlo (MC) methods. It was found that, in contrast to Si/Si systems, the height of the insulating layer cannot be ignored during the evaluation of pitch and linewidth. The thickness (i.e., height) factor does play an important role in the contrast of SEM imaging and the shape of the SE profile in these two-material systems. The mechanism of the influence of insulating layer thickness for imaging was studied in detail. In addition, the SiO2/Si pitch structure with a real rough surface was also studied. This work has significant implications for the study of various kinds of two-material systems and could help to optimize the pitch and gate linewidth measurements.

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ljubinko Timotijevic ◽  
Irfan Fetahovic ◽  
Djordje Lazarevic ◽  
Milos Vujisic

Effects of exposing several insulators, commonly used for various purposes in integrated circuits, to beams of protons have been investigated. Materials considered include silicon dioxide, silicon nitride, aluminium nitride, alumina, and polycarbonate (Lexan). The passage of proton beams through ultrathin layers of these materials has been modeled by Monte Carlo simulations of particle transport. Parameters that have been varied in simulations include proton energy and insulating layer thickness. Materials are compared according to both ionizing and nonionizing effects produced by the passage of protons.


2013 ◽  
Vol 28 (3) ◽  
pp. 308-315 ◽  
Author(s):  
Ljubinko Timotijevic ◽  
Milos Vujisic ◽  
Koviljka Stankovic

The Monte Carlo simulations of charged particle transport are used to investigate the effects of exposing ultra-thin layers of insulators (commonly used in integrated circuits) to beams of protons, alpha particles and heavy ions. Materials considered include silicon dioxide, aluminum nitride, alumina, and polycarbonate - lexan. The parameters that have been varied in simulations include the energy of incident charged particles and insulating layer thickness. Materials are compared according to both ionizing and non-ionizing effects produced by the passage of radiation.


2011 ◽  
Vol 497 ◽  
pp. 127-132 ◽  
Author(s):  
Hui Zhang ◽  
Takuro Tamura ◽  
You Yin ◽  
Sumio Hosaka

We have studied on theoretical electron energy deposition in thin resist layer on Si substrate for electron beam lithography. We made Monte Carlo simulation to calculate the energy distribution and to consider formation of nanometer sized pattern regarding electron energy, resist thickness and resist type. The energy distribution in 100 nm-thick resist on Si substrate were calculated for small pattern. The calculations show that 4 nm-wide pattern will be formed when resist thickness is less than 30 nm. Furthermore, a negative resist is more suitable than positive resist by the estimation of a shape of the energy distribution.


Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 246 ◽  
Author(s):  
Saber Avestan ◽  
Mahmood Ghasemnezhad ◽  
Masoud Esfahani ◽  
Caitlin S. Byrt

Silicon application can improve productivity outcomes for salt stressed plants. Here, we describe how strawberry plants respond to treatments including various combinations of salt stress and nano-silicon dioxide, and assess whether nano-silicon dioxide improves strawberry plant tolerance to salt stress. Strawberry plants were treated with salt (0, 25 or 50 mM NaCl), and the nano-silicon dioxide treatments were applied to the strawberry plants before (0, 50 and 100 mg L−1) or after (0 and 50 mg L−1) flowering. The salt stress treatments reduced plant biomass, chlorophyll content, and leaf relative water content (RWC) as expected. Relative to control (no NaCl) plants the salt treated plants had 10% lower membrane stability index (MSI), 81% greater proline content, and 54% greater cuticular transpiration; as well as increased canopy temperature and changes in the structure of the epicuticular wax layer. The plants treated with nano-silicon dioxide were better able to maintain epicuticular wax structure, chlorophyll content, and carotenoid content and accumulated less proline relative to plants treated only with salt and no nano-silicon dioxide. Analysis of scanning electron microscopic (SEM) images revealed that the salt treatments resulted in changes in epicuticular wax type and thickness, and that the application of nano-silicon dioxide suppressed the adverse effects of salinity on the epicuticular wax layer. Nano-silicon dioxide treated salt stressed plants had increased irregular (smoother) crystal wax deposits in their epicuticular layer. Together these observations indicate that application of nano-silicon dioxide can limit the adverse anatomical and biochemical changes related to salt stress impacts on strawberry plants and that this is, in part, associated with epicuticular wax deposition.


2019 ◽  
Vol 25 (4) ◽  
pp. 903-911 ◽  
Author(s):  
Kerim Tugrul Arat ◽  
Jens Bolten ◽  
Aernout Christiaan Zonnevylle ◽  
Pieter Kruit ◽  
Cornelis Wouter Hagen

AbstractScanning electron microscopy (SEM) is one of the most common inspection methods in the semiconductor industry and in research labs. To extract the height of structures using SEM images, various techniques have been used, such as tilting a sample, or modifying the SEM tool with extra sources and/or detectors. However, none of these techniques focused on extraction of height information directly from top-down images. In this work, using Monte Carlo simulations, we studied the relation between step height and the emission of secondary electrons (SEs) resulting from exposure with primary electrons at different energies. It is found that part of the SE signal, when scanning over a step edge, is determined by the step height rather than the geometry of the step edge. We present a way to quantify this, arriving at a method to determine the height of structures from top-down SEM images. The method is demonstrated on three different samples using two different SEM tools, and atomic force microscopy is used to measure the step height of the samples. The results obtained are in qualitative agreement with the results from the Monte Carlo simulations.


2012 ◽  
Vol 725 ◽  
pp. 231-234
Author(s):  
Masashi Minami ◽  
Yoichi Kamiura

There are two typical methods for silicon oxidation. One is pyrogenic oxidation using oxygen and hydrogen, the other is dry oxidation using oxygen. In this study various properties of these oxidation films were compared. The pyrogenic oxidation in turn could show better characteristic values in the all experiments. Furthermore, once dry oxidation was used even before gate oxidation, we found that dry oxidation made a source of defects generation at surface of the Si substrate.


2018 ◽  
Vol 102 (11) ◽  
pp. 1602-1606
Author(s):  
Eldad Adler ◽  
Darlene Miller ◽  
Oded Rock ◽  
Oriel Spierer ◽  
Richard Forster

AimTo investigate the relationships between corneal suture bacteriology, biofilm and the clinical setting using culture studies and scanning electron microscopy (SEM).MethodsThis is a prospective, observational study of patients with a history of penetrating keratoplasty presenting to a tertiary cornea clinic for routine or symptoms-related corneal suture removal. We documented for each patient the suture clinical setting (quiescent, exposed and keratitis-related), retention time, antimicrobial therapy, bacterial growth on culture studies, and bacterial presence and biofilm coverage on SEM.ResultsThere were significantly different culture positivity rates between the quiescent (8%), exposed (12%) and keratitis-related (60%) suture groups (p=0.039). As expected, keratitis-related sutures had the longest retention time compared with quiescent and exposed ones (p=0.02). The biofilm coverage score was higher for sutures from the keratitis-related and exposed groups, although this trend was not statistically significant (p=0.90). Higher biofilm scores were seen in samples that also yielded a positive culture result (p=0.36) and in samples with bacterial presence on SEM images (p=0.16 and p=0.73). Both of these were important trends but not statistically significant.ConclusionsEvidence for active bacterial and biofilm presence on corneal sutures was found. Corneal sutures should be considered for removal sooner, before becoming exposed and/or keratitis-related. Traditional culture studies and SEM imaging are helpful in investigating biofilm and its clinical importance. More studies of the spectrum of bacterial growth on embedded biomedical devices such as corneal sutures are needed.


1986 ◽  
Vol 69 ◽  
Author(s):  
F. Cembali ◽  
A. M. Mazzone ◽  
M. Servidori

The widespread use of through-oxide implants in Si-MOS technology has prompted many studies to characterize the behaviour of oxygen recoiling from the passivating SiO2 layer into the Si substrate. These studies have given support for the idea that an anomalous formation of defects, which alter the profile of the implanted impurity and the mobility of the free carriers, is connected with the oxygen recoils.


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