A Novel Approach for The Production of Low Dislocation Relaxed Sige Material.

1993 ◽  
Vol 319 ◽  
Author(s):  
A.R. Powell ◽  
S.S. Iyer ◽  
F.K. Legoues
Keyword(s):  
Sige Layer ◽  
Silicon On Insulator ◽  
Buffer Layers ◽  
Threading Dislocation ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Novel Approach ◽  
Transmission Electron ◽  
Silicon Thickness ◽  
Buffer Structure

AbstractIn this growth process a new strain relief mechanism operates, whereby the SiGe epitaxial layer relaxes without the generation of threading dislocations within the SiGe layer. This is achieved by depositing SiGe on an ultrathin Silicon On Insulator, SOl, substrate with a superficial silicon thickness less than the SiGe layer thickness. Initially, the thin Si layer is put under tension due to an equalization of the strain between the Si and SiGe layers. Thereafter, the strain created in the thin Si layer relaxes by plastic deformation. Since the dislocations are formed and glide in the thin Si layer, no threading dislocation is ever introduced into the upper SiGe material, which appeared dislocation free to the limit of the cross sectional Transmission Electron Microscopy (TEM) analysis. We thus have a method for producing very low dislocation, relaxed SiGe films with the additional benefit of an SO substrate. This buffer structure is significantly less than a micrometer in thickness and offers distinct advantages over the thick SiGe buffer layers presently in use.

Stress and Microstructure Evolution in Compositionally Graded Al1-xGaxN Buffer Layers for GaN Growth on Si

2005 ◽  
Vol 892 ◽  
Author(s):  
Xiaojun Weng ◽  
Srinivasan Raghavan ◽  
Elizabeth C Dickey ◽  
Joan M Redwing
Keyword(s):  
Buffer Layer ◽  
Compressive Stress ◽  
Microstructure Evolution ◽  
Buffer Layers ◽  
Threading Dislocation ◽  
Cross Sectional ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Annihilation

AbstractWe have studied the evolution of stress and microstructure of compositionally graded Al1-xGaxN (0 ≤ x ≤1) buffer layers on (111) Si substrates with varying thicknesses. In-situ stress measurements reveal a tensile-to-compressive stress transition that occurs near the half-thickness in each buffer layer. Cross-sectional transmission electron microscopy (TEM) shows a significant reduction in threading dislocation (TD) density in the top half of the buffer layer, suggesting that the compressive stress enhances the threading dislocation annihilation. The composition of the buffer layers varies linearly with thickness, as determined by X-ray energy dispersive spectrometry (XEDS). The composition grading-induced compressive stress offsets the tensile stress introduced by microstructure evolution, thus yielding a tensile-to-compressive stress transition at x ≈ 0.5.

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.

Nanoindentation in Tin/Nbn Multilayers and Thin Films Examined Using Transmission Electron Microscopy

1999 ◽  
Vol 5 (S2) ◽  
pp. 776-777
Author(s):  
S.J. Lloyd ◽  
J.E. Pitchford ◽  
J.M. Molina-Aldareguia ◽  
Z.H. Barber ◽  
M.G. Blamire ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Deformation Structure ◽  
Tem Analysis ◽  
Repeat Distance ◽  
Cross Sectional ◽  
Thin Coatings ◽  
Transmission Electron ◽  
Salt Structure ◽  
Interesting System

Nanoindentation allows the hardness of thin coatings and synthetic multilayer structures to be measured, since indentation depths can be as little as a few 10s of nm. In combination with the cross-sectional transmission electron microscopy (TEM) analysis described here it is possible to observe the deformation structure under an indent, and potentially to understand deformation mechanisms on a nm scale in a wide variety of materials. Synthetic multilayers are a particularly interesting system to investigate. Variations in hardness with the multilayer compositional repeat distance (A) have been reported for several systems. The highest hardnesses, which are in excess of what a simple “rule of mixtures” would predict, occur in nitride multilayers at A ∼5nm. Here we present some preliminary results showing the deformation structure in both a monolithic NbN film and a TiN/NbN multilayer in which both components have the rQck salt structure with lattice parameters 0.424nm (TiN) and 0.439nm (NbN).

Strain Relief in InxGa1−xAs/GaAs Multiple Layer Systems

1992 ◽  
Vol 263 ◽  
Author(s):  
V. Krishnamoorthy ◽  
Y.W. Lin ◽  
R.M. Park
Keyword(s):  
Substrate Material ◽  
Threading Dislocation ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Strain Relief ◽  
Multilayer Systems ◽  
Critical Composition ◽  
Multiple Layer ◽  
Graded Layers ◽  
Strained Layer Superlattices

ABSTRACTIn a recent paper[l] we presented the notion of a “critical composition” of InxGa1−xAs (x=0.18) which when exceeded results in threading dislocation evolution in InxGa1−xAs (x ≥ 0.18) material grown on GaAs. For InxGa1−xAs compositions below x=0.18, threading dislocation evolution occurs in the GaAs substrate material but not in the InxGa1−xAs epitaxial layer material, this phenomenon being attributed to a yield strength mismatch in favor of InxGa1−xAs at the epilayer growth temperature.In this paper we describe recent results concerning an extension of this work to the study of strain relief in multiple layer systems. It was found that large x (x-0.5) InxGa1−xAs/GaAs layers can be grown having extremely low dislocation densities (<104/cm2 ) by step increasing the InxGa1−xAs composition at a series of InxGa1−xAs/InyGa1-yAs heterointerfaces such that a “critical composition difference” is not exceeded at each heterointerface. High resolution x-ray diffraction analysis was used to determine the extent of relaxation in each layer of these multilayer systems. As evidenced by cross-sectional TEM analysis, dislocations propagate only in the underlying material at each heterointerface for suitably selected compositional differences which results in the top InxGa1−xAs layer in such multiple layer schemes having a low dislocation density. It is to be noted that conventional methods for blocking dislocations such as strained layer superlattices and compositionally graded layers were not employed in our multilayer systems.

TEM Analysis of Planar Defects in InGaAsN and GaAs Grown on Ge (001) by MOVPE

2016 ◽  
Vol 675-676 ◽  
pp. 639-642
Author(s):  
Pornsiri Wanarattikan ◽  
Sakuntam Sanorpim ◽  
Somyod Denchitcharoen ◽  
Visittapong Yordsri ◽  
Chanchana Thanachayanont ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Buffer Layer ◽  
Growth Direction ◽  
Dark Field ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Planar Defects ◽  
Transmission Electron ◽  
Gaas Buffer Layer ◽  
Field Emission Electron Microscopy

InGaAsN on Ge (001) is proposed to be a part of the InGaP(N)/InGaAs/InGaAsN/Ge four-junction solar cell to increase a conversion efficiency over 40%. In this work, InGaAsN lattice-matched film and GaAs buffer layer grown on Ge (001) substrate by metal organic vapor phase epitaxy (MOVPE) were examined by transmission electron microscopy (TEM). Electron diffraction pattern of InGaAsN taken along the [110]-zone axis illustrates single diffracted spots, which represent a layer with a uniformity of alloy composition. Cross-sectional bright field TEM image showed line contrasts generated at the GaAs/Ge interface and propagated to the InGaAsN layer. Dark field TEM images of the same area showed the presence of boundary-like planar defects lying parallel to the growth direction in the InGaAsN film and GaAs buffer layer but not in the Ge substrate. TEM images with the (002) and (00-2) reflections and the four visible {111} planes reflections illustrated planar defects which are expected to attribute to antiphase boundaries (APBs). Moreover, the results observed from atomic force microscopy (AFM) and field emission electron microscopy (FE-SEM) demonstrated the surface morphology of InGaAsN film with submicron-sized domains, which is a characteristic of the APBs.

Wafer Bonding of Diamond Films to Silicon for Silicon-on-Insulator Technology

2001 ◽  
Vol 686 ◽  
Author(s):  
Gleb N. Yushin ◽  
Scott D. Wolter ◽  
Alexander V. Kvit ◽  
Ramon Collazo ◽  
John T. Prater ◽  
...  
Keyword(s):  
Wafer Bonding ◽  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Amorphous Layer ◽  
Silicon On Insulator ◽  
Acoustic Microscopy ◽  
Cross Sectional ◽  
Silicon Carbon ◽  
Transmission Electron ◽  
Silicon On Insulator Technology

AbstractPolycrystalline diamond films previously grown on silicon were polished to an RMS roughness of 15 nm and bonded to the silicon in a dedicated ultrahigh vacuum bonding chamber. Successful bonding under a uniaxial mechanical stress of 32 MPa was observed at temperatures as low as 950°C. Scanning acoustic microscopy indicated complete bonding at fusion temperatures above 1150°C. Cross-sectional transmission electron microscopy later revealed a 30 nm thick intermediate amorphous layer consisting of silicon, carbon and oxygen.

Atomic Force Microscopy Study of GaN-Buffer Layers on SiC(0001) By MOCVD

1996 ◽  
Vol 423 ◽  
Author(s):  
Dongsup Lim ◽  
Dongjin Byun ◽  
Gyeungho Kim ◽  
Ok-Hyun Nam ◽  
In-Hoon Choi ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Microscopy Study ◽  
Growth Conditions ◽  
Interfacial Free Energy ◽  
Buffer Layers ◽  
Optimum Growth ◽  
Cross Sectional ◽  
Atomic Force ◽  
Transmission Electron ◽  
Gan Buffer Layer

AbstractBuffer layers promote lateral growth of films due to a decrease in interfacial free energy between the film and substrate, and large 2-dimensional nucleation. Smooth surfaces of thebuffer layers are desired. Optimum conditions for GaN-buffer growth on the vicinal surface of 6H-SiC(0001) were determined by atomic force microscope (AFM). AFM analysis of the GaN nucleation layers led to an optimum growth conditions of the GaN-buffer layer which was confirmed by cross-sectional transmission electron microscopy, Hall measurements and photoluminescence spectra. Optimum growth conditions for GaN-buffer layer on SiC(0001) was determined to be 1 minute growing at 550°C.

Direct Observations of Relaxation of Si/SiGe/Si on Insulator

2010 ◽  
Vol 1262 ◽  
Author(s):  
Tongda Ma ◽  
Hailing Tu
Keyword(s):  
Misfit Dislocation ◽  
Room Temperature ◽  
Sige Layer ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Cross Sectional ◽  
Direct Observations ◽  
Transmission Electron ◽  
Dislocation Behavior ◽  
Film Specimen

AbstractMicrostructural evolution is directly observed when the cross-sectional film specimen of Si/SiGe/Si on insulator (Si/SiGe/SOI) is heated from room temperature (R.T., 291 K) up to 1113 K in high voltage transmission electron microscope (HVEM). The misfit dislocation at the lower interface of the SiGe layer begins to extend downwards even at 913 K. The lower interface takes the lead in roughening against the upper interface of the SiGe layer. The roughened interface is ascribed to elastic relaxation. As misfit strain is partially transferred to SOI top Si layer and misfit dislocation is prolonged at the lower interface, the roughened interface turns smooth again. Thereafter, the misfit dislocations are introduced into the upper roughened interface of the SiGe layer to release the increased misfit strain. It is suggested that the microscopic relaxation of the SiGe layer is related to dislocation behavior and strain transfer.

Cantilever Epitaxy of GaN on Sapphire: Further Reductions in Dislocation Density

2002 ◽  
Vol 743 ◽  
Author(s):  
D. M. Follstaedt ◽  
P. P. Provencio ◽  
D. D. Koleske ◽  
C. C. Mitchell ◽  
A. A. Allerman ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Processing Conditions ◽  
Optimum Growth ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Threading Dislocation Density

ABSTRACTThe density of vertical threading dislocations at the surface of GaN grown on sapphire by cantilever epitaxy has been reduced with two new approaches. First, narrow mesas (<1 μm wide) were used and {11–22} facets formed over them early in growth to redirect dislocations from vertical to horizontal. Cross-sectional transmission electron microscopy was used to demonstrate this redirection and to identify optimum growth and processing conditions. Second, a GaN nuc-leation layer with delayed 3D → 2D growth transition and inherently lower threading dislocation density was adapted to cantilever epitaxy. Several techniques show that a dislocation density of only 2–3×107/cm2 was achieved by combining these two approaches. We also suggest other developments of cantilever epitaxy for reducing dislocations in heteroepitaxial systems.

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