Monoenergetic Positron Beam Studies of Oxygen in Single Crystal Silicon - Stress Induced Clustering of Oxygen Atoms in Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
R. Nagai ◽  
E. Takeda ◽  
Y. Tabuki ◽  
L. Wei ◽  
S. Tanigawa
Keyword(s):  
Silicon Oxide ◽  
Intrinsic Value ◽  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Positron Beam ◽  
Interstitial Oxygen ◽  
Bulk Silicon ◽  
Crystal Silicon ◽  
S Parameter ◽  
Oxygen Atoms

ABSTRACTA monoenergetic positron beam has been used to investigate the state of interstitial oxygen in Czochralski (CZ)-grown Si with either thermally grown S1O2 (100 nm thick) or silicon oxide (p-SiOx) deposited by plasma enhanced chemical vaper deposition technique on the surface. Both the growth of thermal SiO2 and the deposition of SiOx film resulted in a reduction of the doppler-broadening line shape parameter (S-parameter) for the positron annihilation in the bulk silicon region. Annealing at 450δC, the removal of oxide overlayer or long-term aging at room temperature caused the S-parameter to return to its intrinsic value. It was thought that tensile stress in silicon, induced by the thermal oxidation or the deposition of SiOx films which had compressive internal stress themselves, enhanced the rearrangement of oxygen atoms and caused the formation of oxygen clusters in silicon crystal. Oxygen interstitial clusters can trap positrons leading to the lower S-parameter value for annihilation in the bulk silicon region, because of large overlap with core electrons. The above results suggest that oxygen atoms can absorb lattice strain by clustering and thus prevent the generation of dislocations against external stress in the Si lattice. This results yield an additional explanation of the high mechanical strength of CZ Si crystal.

Influences of Silicon Crystal Anisotropy in Nano-Machining Processes Using AFM

2013 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Xinnan Wang
Keyword(s):  
Normal Load ◽  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Transformation Mechanism ◽  
Machining Processes ◽  
Crystal Silicon ◽  
Normal Loading ◽  
Crystal Direction ◽  
Four Levels ◽  
Cutting Mechanisms

Atomic force microscope (AFM) machining has the potential to become an essential technology for manufacturing micro/nano-scale devices. In literature, this technique has been successfully employed to machine various types of materials, including semiconductor materials and metals. However, the effect of material anisotropy in terms of crystal direction is rarely considered in the existing studies. In this paper, we conduct nano-scratching experiments on the (1 0 0) plane of single crystal silicon surface with a diamond tip in an AFM machine. Three levels of crystal direction of nano-scratching are considered. Four levels of normal loading are applied. Machining performances are mainly evaluated by the groove morphology. Also, the wear coefficients and scratch ratio are calculated to the anti-wear performance. Based on the pile up volume and cutting volume respectively, the presence of the ploughing and cutting mechanisms is determined. The experiment results indicate that the applied normal load significantly affect the groove depth and debris morphology. The scratching direction has a pronounced effect on the friction coefficient and the calculated scratching hardness. By observing the debris morphology and cracks formation, the dependence of ductile to brittle transformation mechanism of silicon machining on the crystal direction is also discussed.

Stress and Structural Images of Microindented Silicon by Raman Microscopy

1997 ◽  
Vol 51 (9) ◽  
pp. 1405-1409 ◽  
Author(s):  
Michael Bowden ◽  
Derek J. Gardiner
Keyword(s):  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Structure Defect ◽  
Raman Intensity ◽  
Stress Distributions ◽  
Defect Region ◽  
Crystal Silicon ◽  
Pixel Resolution ◽  
Crack Tips ◽  
Indentation Site

The microline focus spectrometer (MiFS) Raman imaging process is described and is used to investigate stress and structure defect patterns in micro-indented single-crystal silicon. Raman intensity, frequency, and bandwidth images are reported with 0.3-μm pixel resolution, which reveal residual compressive stress distributions around the indentation site and areas of tensile stress at the crack tips. A previously unreported annular structural defect region, remote from the indent site, is observed in images where the indenter tip edges are aligned with the 110 direction of the silicon crystal.

The Effect of Starting Silicon Crystal Structure on Photoluminescence Intensity of Porous Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
W. B. Dubbelday ◽  
S. D. Russell ◽  
K. L. Kavanagh
Keyword(s):  
Porous Silicon ◽  
Single Crystal ◽  
Amorphous Silicon ◽  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Luminescent Materials ◽  
Photoluminescence Intensity ◽  
Crystal Silicon ◽  
Chemical Etch ◽  
Porosity Measurements

ABSTRACTIn previous work we reported that porous silicon (PS) films formed using a dilute HF:HNO3 chemical etch on polycrystalline, implant damaged single crystal, or amorphous starting material have luminescent characteristics that differ from PS fabricated on single crystal silicon1. Polycrystalline and implant damaged porous silicon exhibits brighter luminescence compared to single crystal silicon etched under identical conditions. No photoluminescence is detected from the porous amorphous silicon. In this work these effects are examined using HF:NaNO2 solutions with freely available NO2. The accelerated etching effects from work damage are reduced, and the PS from polycrystalline and implant damaged silicon luminesce with the same intensity as the PS from single crystal silicon. Again, etched amorphous silicon does not luminesce. TEM and EDX porosity measurements are used to determine the differences in structure and etching characteristics between the luminescent and non-luminescent materials.

Effect of Hydrogen on the Mechanical Properties of Silicon Crystal Surface

2013 ◽  
Author(s):  
Hayato Izumi ◽  
Ryota Mukaiyama ◽  
Nobuyuki Shishido ◽  
Shoji Kamiya
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Crystal Surface ◽  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Displacement Curve ◽  
Hydrogen Atoms ◽  
Crystal Silicon ◽  
Boron Doped ◽  
Energy Dissipated

This paper reports the mechanical properties of single crystal silicon surface changed with hydrogen atoms trapped by underwater boiling treatment. Nanoindentaion test using a Berkovich indenter in six different indentation loads ranging from 100 μN to 1000 μN was conducted to obtain the load-displacement curve. The energy dissipated in plastic deformation, i.e. plasticity energy, during indentation on silicon wafers with different carrier concentration (undoped, lightly and heavily boron doped silicon) were compared. After boiling treatment, increment in the plasticity energy was observed on silicon containing boron. This result suggests that hydrogen atoms trapped inside silicon enhanced dislocation mobility leading to larger plastic deformation.

Tissue Compatibility of Silicon Microfabricated Probes Inserted into the Brain

1997 ◽  
Vol 3 (S2) ◽  
pp. 289-290
Author(s):  
J. N. Turner ◽  
William Shain ◽  
D. H. Szarowski ◽  
M. Anderson ◽  
S. Martins ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
Single Crystal Silicon ◽  
Tissue Reaction ◽  
Crystal Silicon ◽  
Silicon Oxide Layer ◽  
Disease States ◽  
Large Numbers ◽  
The Central Nervous System ◽  
High Level ◽  
The Brain

The application of nano- and microfabricated devices based on silicon electronics technology is an emerging interdisciplinary area combining engineering and biology. The placement of electrically active probes in damaged or diseased tissues of the central nervous system could have enormous impact on the health and quality of life of large numbers of individuals by restoring lost function, or by treating or controlling disease states. Such probes have been fabricated at a high level of engineering sophistication. Unfortunately, when inserted into the brain a tissue reaction is initiated forming a scar that surrounds and electrically isolates the probe within a few weeks. This reaction is thought to primarily involve glial cells, and is undoubtedly dominated by the bulk surface of the probes which have a silicon oxide layer on top of single crystal silicon.Model probes (Fig. 1) were microfabricated by photolithography with a 1×1mm tab used for gripping and inserting probes.

Reactions of Photogenerated CF2 and CF3 on Silicon and Silicon Oxide Surfaces

1988 ◽  
Vol 129 ◽  
Author(s):  
John Langan ◽  
J.A. Shorter ◽  
Xu Xin ◽  
J.I. Steinfeld
Keyword(s):  
Silicon Surface ◽  
Silicon Oxide ◽  
Single Crystal Silicon ◽  
Laser Photolysis ◽  
Oxide Surfaces ◽  
Ion Sputtering ◽  
Dissociative Chemisorption ◽  
Crystal Silicon ◽  
Infrared Multiple Photon Dissociation ◽  
Argon Ion

ABSTRACTWe have investigated the reactions of neutral fluorocarbon fragments, generated by laser photolysis of suitable precursors, with single-crystal silicon and thermally deposited silicon oxide surfaces. CF3 free radicals are generated by infrared multiple-photon dissociation of C2F6. While CF3 undergoes dissociative chemisorption on Si, it adsorbs very little on annealed SiO2 surfaces, and even on ion-damaged oxide surfaces, CF3 adsorbs but does not undergo transfer of fluorine from the fluorocarbon to surface silicon atoms. CF2, produced by excimer-laser photolysis of C2F4, is adsorbed on SiO2 surfaces. As with CF3, no transfer of fluorine from carbon to silicon is observed, even after argon-ion sputtering or ultraviolet irradiation of the surface. These measurements have been extended to NF3; this species chemisorbs and dissociates on a silicon surface, but even a monolayer of oxide is sufficient to block this process. A simple model based on the relative strengths of C-F, N-F, Si-F, Si-C, Si-O, and Si-N bonds appears to account for the observed behavior of CF3, CF2, and NF3 species on silicon and silicon oxide surfaces. In other cases, however, a barrier appears to be implicated in the chemisorption process.

scholarly journals A direct evidence of fatigue damage growth inside silicon MEMS structures obtained with EBIC technique

2014 ◽  
Vol 36 (2) ◽  
pp. 109-118
Author(s):  
Vu Le Huy ◽  
Shoji Kamiya
Keyword(s):  
Electron Microscope ◽  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Fatigue Loading ◽  
Scanning Transmission Electron Microscope ◽  
Crystal Silicon ◽  
Oxidation Layer ◽  
Analysis Technique ◽  
Defect Growth ◽  
Scanning Transmission

Electron beam induced current (EBIC) is a semiconductor analysis technique performed in a scanning electron microscope (SEM) or scanning transmission electron microscope (STEM). It is able to sense defects beneath the surface even invisible by SEM. This paper presents the results of a trial to observe the defect growth inside silicon MEMS structures under fatigue loading by applying EBIC technique. The tests were performed on two specimens fabricated from an n-type single crystal silicon wafer. While the test region of the specimens was repeatedly subjected to compressive stress, EBIC images were obtained to visualize damage evolution which presented by the growth of the dark region on EBIC images. It was proved that the damage is not due to the growth of oxidation layer on the surface of the specimens but due to the growth of intrinsic defects of silicon crystal. The results would be evidences to elucidate that the fatigue damages grow inside silicon MEMS structures but not in oxidation layer.

Cluster Computations Related to Silicon Thermal Donors

1985 ◽  
Vol 59 ◽  
Author(s):  
Lawrence C. Snyder ◽  
James W. Corbett
Keyword(s):  
Crystalline Silicon ◽  
Silicon Crystal ◽  
Silicon Monoxide ◽  
Interstitial Oxygen ◽  
Hydrogen Atoms ◽  
Oxygen Complex ◽  
Quantum Chemical Computations ◽  
Silicon Oxygen ◽  
Boron Carbon ◽  
Oxygen Atoms

ABSTRACTAb-initio quantum chemical computations have been applied to a set of molecular clusters derived from Si5 H12 to model defects in crystalline silicon involving boron, carbon, nitrogen, oxygen, and hydrogen. In computations of defect structure, hydrogen atoms terminating silicon valencies are fixed at their computed positions in Si5H12, to represent forces from the lattice, while the position of other atoms are varied.We have computed the stable bonding structures of boron, carbon, nitrogen and oxygen atoms to a vacancy, as well as interstitial oxygen, the silicon-oxygen ylid and two oxygen atoms bound to a vacancy. The structures of the dipositive ions of the oxygen bearing clusters have been computed as part of a search for candidates for the core of the 450° C oxygen thermal donor in silicon crystal. The computed cluster energies are employed to give an account of defect thermochemistry; the addition of the free atoms to a vacancy, the addition of interstitial oxygen atoms to a vacancy, the reaction of interstitial oxygen atoms to form a vacancy-oxygen complex with the emission of silicon monoxide, and the reaction of interstitial oxygen with the dipositive ion of substitutional oxygen to form the dipositive ion of two oxygen atoms bound to a vacancy.

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