Three-phonon Umklapp process in silicon nanowires with square cross sections

2008 ◽  
Vol 245 (8) ◽  
pp. 1512-1516
Author(s):  
Xiang Lü
Keyword(s):  
Cross Sections ◽  
Silicon Nanowires ◽  
Umklapp Process

Wafer-Scale, Highly-Ordered Silicon Nanowires Produced by Step-and-Flash Imprint Lithography and Metal-Assisted Chemical Etching

2012 ◽  
Vol 1512 ◽  
Author(s):  
Jian-Wei Ho ◽  
Qixun Wee ◽  
Jarrett Dumond ◽  
Li Zhang ◽  
Keyan Zang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
High Aspect Ratio ◽  
Chemical Etching ◽  
Semiconductor Device ◽  
Imprint Lithography ◽  
Wafer Level ◽  
Conventional Photolithography ◽  
Metal Assisted Chemical Etching

ABSTRACTA combinatory approach of Step-and-Flash Imprint Lithography (SFIL) and Metal-Assisted Chemical Etching (MacEtch) was used to generate near perfectly-ordered, high aspect ratio silicon nanowires (SiNWs) on 4" silicon wafers. The ordering and shapes of SiNWs depends only on the SFIL nanoimprinting mould used, thereby enabling arbitary SiNW patterns not possible with nanosphere and interference lithography (IL) to be generated. Very densely packed SiNWs with periodicity finer than that permitted by conventional photolithography can be produced. The height of SiNWs is, in turn, controlled by the etching duration. However, it was found that very high aspect ratio SiNWs tend to be bent during processing. Hexagonal arrays of SiNW with circular and hexagonal cross-sections of dimensions 200nm and less were produced using pillar and pore patterned SFIL moulds. In summary, this approach allows highlyordered SiNWs to be fabricated on a wafer-level basis suitable for semiconductor device manufacturing.

scholarly journals Electron transport in silicon nanowires having different cross-sections

2016 ◽  
Vol 7 (2) ◽  
pp. 8-25 ◽  
Author(s):  
Orazio Muscato ◽  
Tina Castiglione
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
Maximum Entropy Principle ◽  
Optical Phonons ◽  
Poisson System ◽  
Moment System ◽  
Entropy Principle ◽  
Closure Relations ◽  
The Moment

AbstractTransport phenomena in silicon nanowires with different cross-section are investigated using an Extended Hydrodynamic model, coupled to the Schrödinger-Poisson system. The model has been formulated by closing the moment system derived from the Boltzmann equation on the basis of the maximum entropy principle of Extended Thermodynamics, obtaining explicit closure relations for the high-order fluxes and the production terms. Scattering of electrons with acoustic and non polar optical phonons have been taken into account. The bulk mobility is evaluated for square and equilateral triangle cross-sections of the wire.

Influence of Surface Effects on the Elastic Properties of Silicon Nanowires with Different Cross Sections

2011 ◽  
Vol 28 (10) ◽  
pp. 106102 ◽  
Author(s):  
Fang Gu ◽  
Jia-Hong Zhang ◽  
Lin-Hua Xu ◽  
Qing-Quan Liu ◽  
Min Li
Keyword(s):  
Elastic Properties ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface Effects

Precision-Cut Crystalline Silicon Nanodots and Nanorods from Nanowires and Direct Visualization of Cross Sections and Growth Orientations of Silicon Nanowires

Nano Letters ◽  
2003 ◽  
Vol 3 (12) ◽  
pp. 1735-1737 ◽  
Author(s):  
Boon K. Teo ◽  
X. H. Sun ◽  
T. F. Hung ◽  
X. M. Meng ◽  
N. B. Wong ◽  
...  
Keyword(s):  
Cross Sections ◽  
Silicon Nanowires ◽  
Crystalline Silicon ◽  
Direct Visualization

Influence of Defects on the Young's Modulus of [110] Silicon Nanowires with Different Cross Sections

2015 ◽  
Vol 645-646 ◽  
pp. 151-156
Author(s):  
Fang Gu ◽  
Jia Hong Zhang ◽  
Min Li ◽  
Lin Yan Liu ◽  
Jing Su
Keyword(s):  
Young’S Modulus ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface Defects ◽  
Young's Modulus ◽  
High Surface ◽  
Surface Effects ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Induced Defects

The size dependence becomes more significant as the devices scale down from micro-to nanodimensions, which is generally attributed to surface effects due to the very high surface-to-bulk ratios in nanoscale structures. However, significant discrepancies between experimental measurements and computational studies indicate that there could be other influences besides surface effects, such as the influences of native oxide layer, fabrication-induced defects and boundary conditions. In this paper, our purpose is to investigate mainly the influence of fabrication-induced defects on the elasticity of [110] silicon nanowires (SiNWs) with different cross sections. We accomplish this by using the molecular dynamics (MD) simulation. Our MD results show that the H-passivated [110] SiNWs without surface defects is slightly elastically softer than bulk, which is in good agreement with other literature MD values. However, the effective Young’s modulus of SiNWs with surface defects can significantly decreases as the defects increase. This softening behavior of [110] SiNWs is severe, which indicates the importance of surface defects. It is noted that the influence of defects on the Young's Modulus of SiNWs strongly depended on the distribution and morphology of defects as well as the cross-sectional shapes of SiNWs. It is observed that the influence of defects on square SiNWs is significantly different from those of hexagonal and triangle SiNWs. Our work reveals that fabrication-induced surface defects could be one of the important origins of the reduced effective Young’s modulus experimentally observed in ultra-thin SiNWs. Therefore, the effect of defects on the characterization of the mechanical properties of nanowire must be carefully considered.

Acceptor Deactivation in Silicon Nanowires Analyzed by Scanning Spreading Resistance Microscopy

2011 ◽  
Vol 178-179 ◽  
pp. 50-55
Author(s):  
Reinhard Kögler ◽  
Xin Ou ◽  
Nadine Geyer ◽  
Pratyush Das Kanungo ◽  
Daniel Schwen ◽  
...  
Keyword(s):  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface Effect ◽  
Bulk Material ◽  
Electrical Characterization ◽  
Volume Ratio ◽  
Ex Situ ◽  
Analysis Method ◽  
Si Nanowires ◽  
Spreading Resistance

Vertical p-type Si nanowires (NWs) "in-situ" doped during growth or "ex-situ" by B ion implantation are investigated regarding their acceptor activation. Due to the much higher surface to volume ratio of the NW in comparison to bulk material the surface effect plays an important role in determining the doping behaviour. Dopant segregation and fixed positive charges at the Si/SiO2 interface result in an acceptor deactivation. The B concentration introduced into the NW has to balance the deactivation effects in order to reach the intended electrical parameters. Scanning spreading resistance microscopy is used for the electrical characterization of the NWs. This analysis method provides images of the local resistivity of NW cross sections. Resistivity data are converted into acceptor concentration values by calibration. The study demonstrates that scanning spreading resistance microscopy is a suitable analysis method capable to spatially and electrically resolve Si NWs in the nanometer-scale. The NW resistivity is found to be size dependent and shows a significant increase as the NW is below 25 nm in diameter. The obtained data can be explained by a core-shell model with a highly conductive NW core and low conductive shell.

Curved Silicon Nanowires with Ribbon-like Cross Sections by Metal-Assisted Chemical Etching

ACS Nano ◽  
2011 ◽  
Vol 5 (6) ◽  
pp. 5242-5248 ◽  
Author(s):  
Jungkil Kim ◽  
Young Heon Kim ◽  
Suk-Ho Choi ◽  
Woo Lee
Keyword(s):  
Cross Sections ◽  
Silicon Nanowires ◽  
Chemical Etching ◽  
Metal Assisted Chemical Etching

scholarly journals A Theoretical and Simulation Analysis of the Sensitivity of SiNWs-FET Sensors

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 121
Author(s):  
Yi Yang ◽  
Zicheng Lu ◽  
Duo Liu ◽  
Yuelin Wang ◽  
Shixing Chen ◽  
...  
Keyword(s):  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface State ◽  
Surface Defects ◽  
Theoretical Study ◽  
Simulation Analysis ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Software Simulation ◽  
Effect Transistor

Theoretical study and software simulation on the sensitivity of silicon nanowires (SiNWs) field effect transistor (FET) sensors in terms of surface-to-volume ratio, depletion ratio, surface state and lattice quality are carried out. Generally, SiNWs-FET sensors with triangular cross-sections are more sensitive than sensors with circular or square cross-sections. Two main reasons are discussed in this article. Firstly, SiNWs-FET sensors with triangular cross-sections have the largest surface-to-volume ratio and depletion ratio which significantly enhance the sensors’ sensitivity. Secondly, the manufacturing processes of the electron beam lithography (EBL) and chemical vapor deposition (CVD) methods seriously affect the surface state and lattice quality, which eventually influence SiNWs-FET sensors’ sensitivity. In contrast, wet etching and thermal oxidation (WETO) create fewer surface defects and higher quality lattices. Furthermore, the software simulation confirms that SiNWs-FET sensors with triangular cross-sections have better sensitivity than the other two types of SiNWs-FET sensors under the same conditions, consistent with the theoretical analysis. The article fully proved that SiNWs-FET sensors fabricated by the WETO method produced the best sensitivity and it will be widely used in the future.

scholarly journals Determination of the Elastic Behavior of Silicon Nanowires within a Scanning Electron Microscope

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Nicole Wollschläger ◽  
Zuhal Tasdemir ◽  
Ines Häusler ◽  
Yusuf Leblebici ◽  
Werner Österle ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
Silicon Nanowire ◽  
Force Sensor ◽  
Native Oxide ◽  
Elastic Behavior ◽  
Show Evidence ◽  
Scanning Electron

Three-point bending tests were performed on double-anchored,110silicon nanowire samples in the vacuum chamber of a scanning electron microscope (SEM) via a micromanipulator equipped with a piezoresistive force sensor. Nanowires with widths of 35 nm and 74 nm and a height of 168 nm were fabricated. The nanowires were obtained monolithically along with their 10 μm tall supports through a top-down fabrication approach involving a series of etching processes. The exact dimension of wire cross sections was determined by transmission electron microscopy (TEM). Conducting the experiments in an SEM chamber further raised the opportunity of the direct observation of any deviation from ideal loading conditions such as twisting, which could then be taken into consideration in simulations. Measured force-displacement behavior was observed to exhibit close resemblance to simulation results obtained by finite element modeling, when the bulk value of 169 GPa was taken as the modulus of elasticity for110silicon. Hence, test results neither show any size effect nor show evidence of residual stresses for the considered nanoscale objects. The increased effect of the native oxide with reduced nanowire dimensions was captured as well. The results demonstrate the potential of the developed nanowire fabrication approach for the incorporation in functional micromechanical devices.

Impact of Cross-Section and Size on Vibration of Silicon Nanowires

2015 ◽  
Vol 645-646 ◽  
pp. 1004-1008 ◽  
Author(s):  
Peng Zhang ◽  
Hong Bo Chen ◽  
Hong Yu
Keyword(s):  
Molecular Dynamics ◽  
Cross Section ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
Surface Effect ◽  
Fundamental Frequencies ◽  
Material Studio ◽  
The Impact ◽  
Article Impact ◽  
Dynamics Method

In this article, impact of cross-section and size on vibration of silicon nanowires is simulated by the molecular dynamics method based on molecular dynamics software Material Studio. The comparison of fundamental frequencies of the silicon nanowires with triangle, diamond, and hexagon cross sections is carried out. The orientations of these silicon nanowires are all in <111> direction. Then we change the length and the width of silicon nanowires to investigate the impact of size on vibration of silicon nanowires. The results show that with the influence of surface effect, the vibration frequency of silicon nanowires strongly depends on cross-section and size.

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