TEM analysis of light emitting porous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1398-1399
Author(s):  
M. W. Cole ◽  
J. F. Harvey ◽  
R.A. Lux ◽  
D.W. Eckart
Keyword(s):  
Porous Silicon ◽  
Integrated Circuits ◽  
Light Emission ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Light Emitting ◽  
Visible Luminescence ◽  
Transmission Electron ◽  
Potential Applications ◽  
Silicon Based

The recent observations of visible light emission from porous silicon layers (PSL) have attracted much interest due to its potential applications in silicon based optoelectronic integrated circuits, optical memories and advanced display systems. To realize these potential applications this material must be fully characterized. Specifically, the microstructure must be studied in order to understand the origin of the light emission. Unfortunately, the issue of the detailed geometry of porous silicon is not fully resolved because of the difficulty in performing transmission electron microscopy (TEM) measurements on these fragile structures. One of the first microstructural studies on visible emitting PSL, presented by Cullis and Canham, showed the material to be composed of needle-like structures having a cross sectional diameter of 3nm. It was suggested that the visible luminescence in this material is due to quantum confinement of these small structures. A major limitation of this work was the method of TEM sample preparation.

Characterization of Chemically Vapor Deposited GaN on Sic on a Simox Substrate

1997 ◽  
Vol 3 (S2) ◽  
pp. 487-488
Author(s):  
W.L. Zhou ◽  
P. Pirouz
Keyword(s):  
Lattice Mismatch ◽  
Defect Density ◽  
Silicon Layer ◽  
Large Defect ◽  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Transmission Electron ◽  
Potential Applications ◽  
Gan Film

GaN has been intensively studied because of its potential applications for the fabrication of blue- or ultraviolet-light emitting devices. Sapphire (α-Al2O3) is generally used as the substrate for growth of GaN film. However, the large lattice mismatch between GaN and Al2O3is a possible cause of the large defect density in the GaN films. Consequently, alternative substrates are being studied with the aim of growing films of lesser defect densities and improved opto-electronic properties. In this paper, we report a transmission electron microscopy (TEM) study of a GaN film grown on cubic SiC which has been obtained by carbonization of the top silicon layer of a SIMOX substrate, i.e. the system GaN/SiC/Si/SiO2/Si.Cross-sectional TEM specimens were prepared by the conventional sandwich technique with the foil surface normal to the Si[l10] direction. The composite sample was ground and dimpled to a thickness of ∼ 10μm, and subsequently ion thinned to electron transparency.

Blue Light Emission from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
X. Y. Hou ◽  
G. Shi ◽  
W. Wang ◽  
F. L. Zhang ◽  
P. H. Hao ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Blue Light ◽  
Light Emission ◽  
Green Light ◽  
Blue Shift ◽  
Blue Light Emission ◽  
Light Emitting ◽  
Visible Luminescence ◽  
Infrared Reflection ◽  
Green Light Emission

ABSTRACTThrough a post treatment of light emitting porous silicon in boilingwater, a large blue shift of its photoluminescence (PL) spectrum hasbeen observed and a stable blue-green light emission at the peak wavelength down to 500 nm is achieved. The effect of boiling water treatment is suggested to be a kind of oxidation, which could reduce thesize of the Si column, fill up some micropores and strengthen the Siskeleton. The photoluminescence microscopic observation shows that the surface of blue light emitting porous silicon is composed of manysmall uniformly light-emitting domains at the size of several tens of μm. Fourier transform infrared reflection (FTIR) measurements show that the formation of Si-H bonds is not responsible for the visible luminescence in the very thin Si wires.

Light Emission from Porous Silicon Subjected to Rapid Thermal Oxidation

1992 ◽  
Vol 283 ◽  
Author(s):  
A. G. Cullis ◽  
L. T. Canham ◽  
G. M. Williams ◽  
P. W. Smith ◽  
O. D. Dosser
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Porous Silicon ◽  
Light Emission ◽  
Porous Si ◽  
Light Emitting ◽  
X Ray ◽  
Amorphous Phases ◽  
Transmission Electron ◽  
Si Nanostructures

ABSTRACTLuminescent oxidised porous Si is produced by rapid thermal annealing of the anodised material in a dry oxygen ambient. Its light-emitting properties are studied by both photoluminescence and cathodoluminescence methods. The structure of the oxidised material is examined by transmission electron microscopy, while its oxygen content is determined by X-ray microanalysis. These investigations show that crystalline Si nanostructures remain in the oxidised porous material and account for its luminescence properties. The work demonstrates that the speculated importance of either Si-based amorphous phases or the interesting material, siloxene, in this regard is unrealistic.

Surface and optical properties of porous silicon

1996 ◽  
Vol 11 (2) ◽  
pp. 305-320 ◽  
Author(s):  
S. M. Prokes
Keyword(s):  
Porous Silicon ◽  
Light Emission ◽  
Semiconductor Industry ◽  
Radiative Transition ◽  
Emission Process ◽  
Carrier Recombination ◽  
Quantum Size ◽  
Visible Luminescence ◽  
Weak Light ◽  
Silicon Based

Although silicon is the material of choice in the semiconductor industry, it has one serious disadvantage: it is an extremely poor optoelectronic material. This is because it is an indirect gap semiconductor, in which radiative transition results in extremely weak light emission in the infrared part of the spectrum. Thus, the discovery of strong visible luminescence from a silicon-based material (porous silicon) has been quite surprising and has generated significant interest, both scientific and technological. This material differs from bulk silicon in one important way, in that it consists of interconnected silicon nanostructures with very large surface to volume ratios. Although the first mechanism proposed to explain this emission process involved carrier recombination within quantum size silicon particles, more recent work has shown that the surface chemistry appears to be the controlling factor in this light emission process. Thus, the aim of this work is to outline the data and arguments that have been presented to support the quantum confinement model, along with the shortcomings of such a model, and to examine more recent models in which the chemical and structural properties of the surface regions of the nanostructures have been incorporated.

Nano-Order Structural Analysis of White Light-Emitting Silicon Oxide Prepared by Successive Thermal Carbonization/Oxidation of the Porous Silicon

2007 ◽  
Vol 561-565 ◽  
pp. 1127-1130 ◽  
Author(s):  
Shunsuke Muto ◽  
A.V. Vasin ◽  
Yukari Ishikawa ◽  
Noriyoshi Shibata ◽  
Jarno Salonen ◽  
...  
Keyword(s):  
Porous Silicon ◽  
White Light ◽  
Silicon Oxide ◽  
Light Emission ◽  
Strong Light ◽  
Light Emitting ◽  
Energy Filtering ◽  
Transmission Electron ◽  
Oxidation By Water ◽  
Electron Energy Loss

Recently the present authors’ group found that porous silicon showed strong and stable white/white-blue light emission after successive thermal carbonization and oxidation by water vapor. This material can be considered as a price-competitive solid-state white-light source. We examined these layers by electron energy-loss spectroscopy (EELS), energy-filtering transmission electron microscopy (EFTEM). The EEL spectra indicated that the silicon skeleton in the porous layer was completely oxidized by the thermal treatment in wet argon ambient and multi-types of carbon phases were present in the 1073 K oxidized sample of stronger emission, while carbon complexes including Si and/or O were formed in the 1223 K oxidized sample of weaker light emission. EF-TEM images showed that carbon/oxygen were more uniformly distributed in the 1223 K oxidized sample. It is assumed that the strong light-emitting properties are controlled by the size and internal chemical bonding states of carbon clusters incorporated.

Visible Light Emission in Silicon-Interface Adsorbed Gas Superlattices

1994 ◽  
Vol 358 ◽  
Author(s):  
Raphael Tsu ◽  
Jonder Morais ◽  
Amanda Bowhill
Keyword(s):  
Light Emission ◽  
Compound Semiconductors ◽  
Light Emitting ◽  
Adsorbed Gas ◽  
Quantum Size ◽  
Visible Luminescence ◽  
New Type ◽  
Silicon Based ◽  
Silicon Interface ◽  
Visible Light Emission

ABSTRACTHaving an indirect fundamental bandgap, unlike III-V or II-VI compound semiconductors, silicon has not played a role in optoelectronic applications such as injection lasers and light emitting diodes. In an attempt to introduce a sufficient quantum size effect, we present the experimental results on a new type of silicon based superlattices consisting of alternating layers of silicon and monolayers of adsorbed gases, Si/IAG multilayers (Si/Interface Adsorbed Gas), constructed by repeated interruptions of silicon deposition with adsorbed gases of oxygen and hydrogen. Fairly strong visible luminescence has been observed.

Visible Luminescence from Silicon: Quantum Confinement or Siloxene?

1992 ◽  
Vol 262 ◽  
Author(s):  
M. S. Brandt ◽  
H. D. Fuchs ◽  
A. Höpner ◽  
M. Rosenbauer ◽  
M. Stutzmann ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Quantum Confinement ◽  
Alternative Explanation ◽  
Present Model ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Visible Luminescence ◽  
Amorphous Si ◽  
Silicon Based ◽  
Raman And Ir Spectroscopy

ABSTRACTThe discovery of strong visible photoluminescence at room temperature from porous silicon has triggered new hope that light-emitting devices compatible with existing Si-technology might become possible. We first review the luminescence behavior observed in silicon-based materials such as amorphous Si, microcrystalline Si, or SiO2. We then critically discuss the present model for the luminescence from porous silicon based on quantum confinement in view of the growing experimental evidence for the importance of both hydrogen and oxygen to obtain efficient luminescence from this material. We propose an alternative explanation based on the presence of siloxene (SieO3H6) in porous silicon which is corroborated by experimental results obtained with photoluminescence, Raman and IR spectroscopy. An important aspect is that siloxene can be prepared by methods different from anodic oxidation, and one particular technique will be described together with possible ways to tune the luminescence energy.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

A Working Method for Adapting the (SEM) Scanning Electron Microscope to Produce (STEM) Scanning Transmission Electron Microscope Images

2002 ◽  
Author(s):  
Edward Coyne
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Theoretical Idea ◽  
Cross Sectional ◽  
Additional Advantage ◽  
Transmission Electron ◽  
Resolution Element ◽  
Scanning Electron

Abstract This paper describes the problems encountered and solutions found to the practical objective of developing an imaging technique that would produce a more detailed analysis of IC material structures then a scanning electron microscope. To find a solution to this objective the theoretical idea of converting a standard SEM to produce a STEM image was developed. This solution would enable high magnification, material contrasting, detailed cross sectional analysis of integrated circuits with an ordinary SEM. This would provide a practical and cost effective alternative to Transmission Electron Microscopy (TEM), where the higher TEM accelerating voltages would ultimately yield a more detailed cross sectional image. An additional advantage, developed subsequent to STEM imaging was the use of EDX analysis to perform high-resolution element identification of IC cross sections. High-resolution element identification when used in conjunction with high-resolution STEM images provides an analysis technique that exceeds the capabilities of conventional SEM imaging.

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