Effects of Implant Temperature on Disordering of AlAs-GaAs Superlattices

1986 ◽  
Vol 77 ◽  
Author(s):  
E. A. Dobisz ◽  
B. Tell ◽  
H. G. Craighead ◽  
S. A. Schwarz ◽  
M. C. Tamargo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Sectional ◽  
Bulk Gaas ◽  
Directional Diffusion ◽  
Transmission Electron ◽  
Silicon Impurity ◽  
Secondary Ion ◽  
Mass Spectro ◽  
Superlattice Period

ABSTRACTThe effect of implant temperature, superlattice period, and directional diffusion has been studied for silicon impurity-enhanced compositional disordering of GaAs-AlAs superlattices (SL) of 9 ran and 16 nm period. The SL were implanted with Si at temperatures of 483 K, 293 K, and 77 K, with an energy of 100 keV and dose of 2.5 × 1014 cm-2. These were examined by cross-sectional transmission electron microscopy and secondary ion mass spectro-scopy for structural and compositional information. The damage due to implantation prior to annealing is strikingly less for superlattices than for bulk GaAs. All annealed samples exhibited disordering, with the 9 nm period SL exhibiting a deeper disordered region than the 16 nm SL. The greatest enhancement was found in the 9 nm period SL implanted at 77 K, in which the disordering extended from a depth of 25 nm to =300 nm. The mixing was found to be anisotropie, with the SL mixing propagating greater in depth than in the lateral directions. The result has important implications for high resolution patterning possibilities with this method.

Implant Damage in AlGaAs Based Superlattices and Alloys at 77K

1989 ◽  
Vol 147 ◽  
Author(s):  
E. A. Dobisz ◽  
H. Dietrich ◽  
A. W. McCormick ◽  
J. P. Harbison
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layer Thickness ◽  
Room Temperature ◽  
Amorphous Layer ◽  
Current Work ◽  
Cross Sectional ◽  
Bulk Gaas ◽  
Transmission Electron ◽  
Extensive Damage

AbstractPreviously, it was shown that superlattices implanted with Si at 77K, exhibited more extensive damage and uniform compositional mixing upon subsequent annealing than samples implanted at room temperature.[l,2] The current work focuses on the damage in samples implanted with Si at 77K. The study shows that for a given dose, the amount of damage depends upon the layer thickness and the composition. Specimens of bulk GaAs, Al 3Ga. 7As, 7.5 nm GaAs -10 nm Al. 3Ga. 7As superlattice (SL1), 5.5 nm GaAs −3.5 nm AlAs superlattice (SL2), and 8.0 nm GaAs −8.0 nm AlAs superlat-tice (SL3) were implanted at 77K with 100 KeV Si, with doses ranging from 3 × 1013 cm−2 to 1 × 1015 cm−2. The samples were examined by ion channelling and cross sectional transmission electron microscopy (TEM). At 77K and a dose of 1 × 1014 cm−2, the GaAs and SLi showed an amorphous layer, while no damage peak was observed in SL2. The 77K amorphization thresholds of the Al 3Ga. 7As alloy, SL2, and SL3 were 2.5 × 1014 cm−2, 4 × 1014 cm−2, and 1 × 1015 cm−2 respectively. The sharpness of the amorphization threshold varied with the material.

Non-Destructive Characterisation of Rapid Thermally Annealed N+-Doped Polysilicon Using Spectroscopic Ellipsometry

1995 ◽  
Vol 406 ◽  
Author(s):  
R. T. Carline ◽  
W. Y. Leong ◽  
A. G. Cullis ◽  
M. R. Houlton ◽  
D. A. Hope
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spectroscopic Ellipsometry ◽  
Impurity Distribution ◽  
Refractive Indices ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Non Destructive ◽  
Secondary Ion ◽  
Anneal Temperature

AbstractThe use of spectroscopic ellipsometry (SE) to characterise the effects of rapid thermal annealing on Si implanted with phosphorous and phosphorous with fluorine are presented. Variations in the measured SE spectra with anneal temperature and presence/absence of fluorine are clearly observed. Spectra are successfully modelled using refractive indices which are graded with depth. Comparison with cross-sectional transmission-electron microscopy and secondary ion mass spectroscopy show that the results can be correlated with both the crystallinity and impurity distribution in the poly-Si.

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.

Ion thinning of integrated circuit transverse specimens for transmission electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1426-1427
Author(s):  
F. Shaapur
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Integrated Circuit ◽  
Substrate Surface ◽  
Homogeneous Material ◽  
Material System ◽  
Ion Milling ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Motion Profile

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.

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.

Post Oxidation Anneal and Re-Oxidation Effects in 5 nm SiO2 Films

1986 ◽  
Vol 76 ◽  
Author(s):  
L. Dori ◽  
M. Arienzo ◽  
Y. C. Sun ◽  
T. N. Nguyen ◽  
J. Wetzel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Dioxide ◽  
Oxygen Vacancies ◽  
Interface Roughness ◽  
Cross Sectional ◽  
Oxide Charge ◽  
Transmission Electron ◽  
Redistribution Of Hydrogen ◽  
Transmission Electron Microscopy Cross

ABSTRACTUltrathin silicon dioxide films, 5 nm thick, were grown in a double-walled furnace at 850°C in dry O2. A consistent improvement in the electrical properties is observed following the oxidation either with a Post-Oxidation Anneal (POA) at 1000°C in N2 or with the same POA followed by a short re-oxidation (Re-Ox) step in which 1 nm of additional oxide was grown. We attribute these results to the redistribution of hydrogen and water related groups as well as to a change in the concentration of sub-oxide charge states at the Si-SiO2 interface. A further improvement observed after the short re-oxidation step had been attributed to the filling of the oxygen vacancies produced during the POA. High resolution Transmission Electron Microscopy cross-sectional observations of the Si-iSO2 interface have evidenced an increase in the interface roughness after the thermal treatment at high temperature. These results are in agreement with recent XPS data.

Photo Modified Growth of GaAs by Chemical Beam Epitaxy

1998 ◽  
Vol 510 ◽  
Author(s):  
R. Jothilingam ◽  
T. Farrell ◽  
T.B. Joyce ◽  
P.J. Goodhew
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Rate ◽  
Electrical Power ◽  
Xenon Lamp ◽  
Chemical Beam Epitaxy ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
Laser Reflectometry

AbstractWe report the photo modified growth of GaAs by chemical beam epitaxy at substrate temperatures in the range 335 to 670°C using triethygallium (TEG) and arsine. A mercury-xenon lamp (electrical power 200 W) provided the irradiation for the photoassisted growth. The growth was monitored in real time by laser reflectometry (LR) using a 670 nm semiconductor laser, and the optically determined growth rate agreed with that obtained from the layer thickness measured by cross sectional transmission electron microscopy. The observed photo-enhancement of the growth rate at low substrate temperatures and inhibition at high substrate temperatures is thermal in origin, consistent with raising the substrate temperature by 10±3°C. Cross sectional transmission electron microscopy showed that the photoassisted layers are essentially free from dislocations

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