Quantitative Experimental Determination of The Effect of Dislocation - Dislocation Interactions on Strain Relaxation in Lattice Mismatched Heterostructures

1998 ◽  
Vol 535 ◽  
Author(s):  
E. A. Stach ◽  
R. Hull ◽  
R. M. Tromp ◽  
F. M. ROSS ◽  
M. C. Reuter ◽  
...  
Keyword(s):  
Electronic Device ◽  
Blocking Probability ◽  
Strain Relaxation ◽  
Interaction Force ◽  
Strained Layers ◽  
Dislocation Interaction ◽  
Transmission Electron ◽  
Dislocation Interactions ◽  
Device Applications ◽  
Gap States

AbstractWe present real time observations of the interaction of dislocations in heteroepitaxial strained layers using a specially modified ultrahigh vacuum transmission electron microscope equipped with in-situ deposition capabilities. These observations have led to delineation of the regime of epilayer thickness and composition where dislocation interactions result in blocking of the propagating threading segment. It is found that both the blocking probability as well as the magnitude of the dislocation interaction force are strongly dependent on the Burgers vectors of the dislocations involved, with the greatest effects observed when the Burgers vectors of the two dislocations are parallel with respect to each other. Frame-by-frame analysis of the motion of the dislocation threading segment during interaction is used to extract the magnitude of the interaction stresses as a function of both the level of heteroepitaxial strain and the dislocation geometry. Finally, by continuing growth following observations of blocking during annealing, we find that blocked dislocations are likely to remain in that configuration until substantial additional heteroepitaxial stresses are incorporated into the layer. These results have direct relevance to the successful integration of strained layer heterostructures into electronic device applications. This is because blocked threading segments result in the introduction of undesired band gap states, enhance impurity diffusion, modify surface morphology and act to limit the dislocation density reductions achievable in graded buffer structures.

TEM study of CdS nanocrystals formed in SiO2 by ion implantation

1996 ◽  
Vol 54 ◽  
pp. 236-237
Author(s):  
Jane G. Zhu ◽  
C. W. White ◽  
J. D. Budai ◽  
S. P. Withrow
Keyword(s):  
Ion Implantation ◽  
Electronic Device ◽  
Semiconductor Nanocrystals ◽  
Optical Nonlinearity ◽  
Silicon Substrates ◽  
Cds Nanocrystals ◽  
Quantum Confinement Effects ◽  
Transmission Electron ◽  
Device Applications ◽  
Ion Profiles

Quantum confinement effects and enhanced optical nonlinearity are expected from II-VI semiconductor nanocrystals, which are important for novel opto-electronic device applications. The ion implantation method has been used in our study to form CdS nanocrystals inside amorphous SiO2. The CdS nanocrystals were studied by transmission electron microscopy (TEM).The samples were implanted (at room temperature) with equal doses (1×1017 ions/cm2) of Cd and S into a SiO2 layer on (100) silicon substrates and then annealed under Ar + 4%H2 ambient at 800°C and 1000°C for 1 h. Implant energies were chosen to overlap the Cd and S ion profiles in the middle of the oxide layer. CdS precipitates are formed during the thermal annealing.The effect of annealing temperatures on the nanocrystals size distributions are revealed in Figs. 1 and 2. The sizes of CdS nanocrystals are in the range of 2 - 11 nm for the sample annealed at 800°C, and in the range of a few to 16 nm for the sample annealed at 1000°C.

Solid Phase Epitaxy of Si1-xGex on Si Strained Layers

1989 ◽  
Vol 160 ◽  
Author(s):  
B.J. Robinson ◽  
B.T. Chilton ◽  
P. Ferret ◽  
D.A. Thompson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid Phase ◽  
Strain Relaxation ◽  
Crystal Quality ◽  
Solid Phase Epitaxy ◽  
Strained Layers ◽  
Transmission Electron ◽  
Layer Structures

AbstractSingle strained layer structures of up to 30 nm of Si1-xGex. on (100) Si and capped with 30-36 nm of Si have been amorphized by implantation with 120 keV As . The amorphized region, extending to a depth of 130 nm, has been regrown by solid phase epitaxy (SPE) at 600°C. Characterization of the regrown structure by Rutherford backscattering/channeling techniques and transmission electron microscopy indicates that for x < 0.18 the SPE process results in the recovery of strain, while for x > 0.18 there is increasing strain relaxation and a deterioration of crystal quality.

A Systematic Investigation of Strain Relaxation, Surface Morphology and Defects in Tensile and Compressive InGaAs/InP Layers

1999 ◽  
Vol 578 ◽  
Author(s):  
C. Ferrari ◽  
L. Lazzarini ◽  
G. Salviati ◽  
M. Natali ◽  
M. Berti ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Scanning Force Microscopy ◽  
Systematic Investigation ◽  
Misfit Dislocations ◽  
Extended Defects ◽  
Strained Layers ◽  
Planar Defects ◽  
Transmission Electron ◽  
Metal Organic ◽  
Scanning Force

AbstractThe results of a systematic investigation by transmission electron microscopy (TEM), cathodoluminescence (CL), Rutherford backscattering (RBS), X-ray diffraction and topography and scanning force microscopy (SFM) techniques on several InGaAs/InP compressive and tensile strained layers covering the misfit range from −2.3 to 1.5×10−2 and grown by the metal organic vapor phase epitaxy (MOVPE) technique are reported. In compressively strained films the same dependence for the residual strain vs the film thickness as for the InGaAs/GaAs is found whereas a different strain release rate and different extended defects are found in tensile stressed InGaAs alloy. In particular in tensile stressed samples, grooves, planar defects and cracks are present in addition to the interfacial network of misfit dislocations. The correlation between the observed planar defects and the mechanisms of strain relaxation in the case of tensile strained layers is discussed.

Microstructure of GaAs nanocrystals formed inside single crystalline silicon

1996 ◽  
Vol 54 ◽  
pp. 968-969
Author(s):  
Jane G. Zhu ◽  
C. W. White ◽  
J. D. Budai ◽  
M. J. Yacaman ◽  
G. Mondragon
Keyword(s):  
Electronic Device ◽  
Crystalline Silicon ◽  
Semiconductor Nanocrystals ◽  
Implantation Technique ◽  
Single Crystalline Silicon ◽  
Semiconductor Technology ◽  
Cross Sectional ◽  
Si Substrates ◽  
Transmission Electron ◽  
Device Applications

Semiconductor nanocrystals exhibit novel properties that are important for electronic and opto-electronic device applications. Many methods have been developed to synthesize semiconductor nanocrystals. Among them is the ion implantation technique, which is compatible with the semiconductor technology. It has been recently reported that the compound semiconductor GaAs can be formed inside Si by sequential implantation of Ga and As and thermal annealing.In this study, GaAs nanocrystals were formed by sequential implantation of As and Ga, with the same dose of 1 x 1017 cm-2, into (100) Si substrates at 550°C. The implantation energies were chosen so that the Ga and As ions are overlapped over a few hundred nanometers in depth. The samples were then annealed at 1000°C for 1 h in flowing Ar + 4%H2 atmosphere to form GaAs precipitates. Transmission electron microscopy (TEM) has been used to study the microstructures of these samples.The cross-sectional TEM image in Fig. 1 shows the GaAs precipitates formed inside the Si substrateimplanted with As and then Ga.

Electronic Cone Illumination with the Conventional Transmission Electron Microscope

1977 ◽  
Vol 35 ◽  
pp. 72-73
Author(s):  
William Krakow
Keyword(s):  
Electronic Device ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Hollow Cone ◽  
Transmission Electron ◽  
Lissajous Figures ◽  
High Resolution Images ◽  
Imaging Mode ◽  
Diffraction Patterns ◽  
Transmission Microscope

An electronic device has been constructed which manipulates the primary beam in the conventional transmission microscope to illuminate a specimen under a variety of virtual condenser aperture conditions. The device uses the existing tilt coils of the microscope, and modulates the D.C. signals to both x and y tilt directions simultaneously with various waveforms to produce Lissajous figures in the back-focal plane of the objective lens. Electron diffraction patterns can be recorded which reflect the manner in which the direct beam is tilted during exposure of a micrograph. The device has been utilized mainly for the hollow cone imaging mode where the device provides a microscope transfer function without zeros in all spatial directions and has produced high resolution images which are also free from the effect of chromatic aberration. A standard second condenser aperture is employed and the width of the cone annulus is readily controlled by defocusing the second condenser lens.

TEM and cathodoluminescence of precipitates in II-VI semiconductors

1988 ◽  
Vol 46 ◽  
pp. 488-489
Author(s):  
Joanna L. Batstone
Keyword(s):  
Crystal Growth ◽  
Band Gap ◽  
Local Strain ◽  
Wide Band ◽  
Optoelectronic Device ◽  
Wide Band Gap ◽  
Bulk Crystal Growth ◽  
Transmission Electron ◽  
Device Applications ◽  
Stoichiometry Control

Interest in II-VI semiconductors centres around optoelectronic device applications. The wide band gap II-VI semiconductors such as ZnS, ZnSe and ZnTe have been used in lasers and electroluminescent displays yielding room temperature blue luminescence. The narrow gap II-VI semiconductors such as CdTe and HgxCd1-x Te are currently used for infrared detectors, where the band gap can be varied continuously by changing the alloy composition x.Two major sources of precipitation can be identified in II-VI materials; (i) dopant introduction leading to local variations in concentration and subsequent precipitation and (ii) Te precipitation in ZnTe, CdTe and HgCdTe due to native point defects which arise from problems associated with stoichiometry control during crystal growth. Precipitation is observed in both bulk crystal growth and epitaxial growth and is frequently associated with segregation and precipitation at dislocations and grain boundaries. Precipitation has been observed using transmission electron microscopy (TEM) which is sensitive to local strain fields around inclusions.

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

Defect morphology in thick relaxed layers of InGaAs on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 668-669
Author(s):  
R H Dixon ◽  
P Kidd ◽  
P J Goodhew
Keyword(s):  
Electron Microscopy ◽  
Surface Morphology ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Strained Layers ◽  
Good Surface ◽  
Transmission Electron ◽  
Device Structures ◽  
Surface Morphologies

Thick relaxed InGaAs layers grown epitaxially on GaAs are potentially useful substrates for growing high indium percentage strained layers. It is important that these relaxed layers are defect free and have a good surface morphology for the subsequent growth of device structures.3μm relaxed layers of InxGa1-xAs were grown on semi - insulating GaAs substrates by Molecular Beam Epitaxy (MBE), where the indium composition ranged from x=0.1 to 1.0. The interface, bulk and surface of the layers have been examined in planar view and cross-section by Transmission Electron Microscopy (TEM). The surface morphologies have been characterised by Scanning Electron Microscopy (SEM), and the bulk lattice perfection of the layers assessed using Double Crystal X-ray Diffraction (DCXRD).The surface morphology has been found to correlate with the growth conditions, with the type of defects grown-in to the layer (e.g. stacking faults, microtwins), and with the nature and density of dislocations in the interface.

scholarly journals Topological electronics

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Matthew J. Gilbert
Keyword(s):  
Information Processing ◽  
Physical Properties ◽  
Materials Science ◽  
Electronic Device ◽  
Condensed Matter ◽  
Topological Phases ◽  
Applied Physics ◽  
New Paradigm ◽  
Topological Materials ◽  
Device Applications

AbstractWithin the broad and deep field of topological materials, there are an ever-increasing number of materials that harbor topological phases. While condensed matter physics continues to probe the exotic physical properties resulting from the existence of topological phases in new materials, there exists a suite of “well-known” topological materials in which the physical properties are well-characterized, such as Bi2Se3 and Bi2Te3. In this context, it is then appropriate to ask if the unique properties of well-explored topological materials may have a role to play in applications that form the basis of a new paradigm in information processing devices and architectures. To accomplish such a transition from physical novelty to application based material, the potential of topological materials must be disseminated beyond the reach of condensed matter to engender interest in diverse areas such as: electrical engineering, materials science, and applied physics. Accordingly, in this review, we assess the state of current electronic device applications and contemplate the future prospects of topological materials from an applied perspective. More specifically, we will review the application of topological materials to the general areas of electronic and magnetic device technologies with the goal of elucidating the potential utility of well-characterized topological materials in future information processing applications.

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