Crystal Defects In Gan On (0001) Sapphire

1997 ◽  
Vol 482 ◽  
Author(s):  
Matthew T. Johnson ◽  
Zhigang Mao ◽  
C. Barry Carter
Keyword(s):  
Dark Field ◽  
Crystal Defects ◽  
Growth Surface ◽  
Threading Dislocation ◽  
Defect Structures ◽  
Plan View ◽  
Planar Defects ◽  
Dark Field Imaging ◽  
Inversion Domain ◽  
Different Types

AbstractDefect structures in GaN thin films grown on (0001) sapphire have been studied using a combination of different transmission electron microscopy (TEM) techniques. Two fundamentally different types of defects are found in these films. Planar defects which lie on planes perpendicular to the growth surface are common. In some regions of the films, other planar defects are present which run parallel to the surface of the substrate. The terminology used to describe these different defects varies quite widely in the literature and includes combinations of antiphase (inversion) domain boundaries and stacking faults. The second type of defect is generally referred to as a threading dislocation since many thread through the whole thickness of the film. Dislocations with different Burgers vectors have been identified in this work and in previous studies; these dislocations usually have a component of their Burgers vector lying normal to the (0001) plane. The overall defect structures in these films have been characterized using conventional bright-field and dark-field imaging. The detailed structure of the individual defects have been examined using weak-beam microscopy both in plan view and in cross section. This paper illustrates the different types of defects, both planar and linear, compares them to defects which have been characterized more thoroughly in related materials, and discuss the nomenclature of the different defect configurations.

Tem Investigation of Al0.5Ga0.5As1-y Sby Buffer Layer Systems

1997 ◽  
Vol 484 ◽  
Author(s):  
E. Chen ◽  
J. S. Ahearn ◽  
K. Nichols ◽  
P. Uppal ◽  
D. C. Paine
Keyword(s):  
Buffer Layer ◽  
Active Regions ◽  
Dark Field ◽  
Layer Growth ◽  
Buffer Layers ◽  
Growth Surface ◽  
Threading Dislocation ◽  
Misfit Dislocations ◽  
Plan View ◽  
Dark Field Imaging

AbstractWe report on a TEM study of Sb-adjusted quaternary Al0.5Ga0.5As1-y Sby buffer-layers grown on <001> GaAs substrates. A series of structures were grown by MBE at 470°C that utilize a multilayer grading scheme in which the Sb content of Al0.5Ga0.5As1-ySby is successively increased in a series of eight 125 nm thick layers. Post growth analysis using conventional bright field and weak beam dark field imaging of these buffer layers in cross-section reveals that the interface misfit dislocations are primarily of the 60° type and are distributed through out the interfaces of the buffer layer. Plan view studies show that the threading dislocation density in the active regions of the structure (approximately 2 μm from the GaAs substrate) is 105–6/cm2 which is comparable to equivalent InxGa1−x As buffers. Weak Sb-As compositional modulations with a period of 1.8 nm were observed that provide a marker for establishing the planarity of the growth process. These features reveal that the growth surface remains planar through out the buffer layer growth sequence.

Inversion Domain Boundaries in GaN Grown on Sapphire

1996 ◽  
Vol 449 ◽  
Author(s):  
L. T. Romano ◽  
J.E. Northrup
Keyword(s):  
Dark Field ◽  
Hydride Vapor Phase Epitaxy ◽  
Dark Field Imaging ◽  
Inversion Domain ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Convergent Beam ◽  
Inversion Domain Boundaries ◽  
Field Imaging ◽  
Beam Diffraction

ABSTRACTInversion domain boundaries (IDBs) in GaN grown on sapphire (0001) were studied by a combination of high resolution transmission electron microscopy, multiple dark field imaging, and convergent beam diffraction. Films grown by molecular beam epitaxy (MBE), metalorganic vapor deposition (MOCVD), and hydride vapor phase epitaxy (HVPE) were investigated and all found to contain IDBs. Inversion domains (IDs) that extended from the surface to the interface were found to be columnar with facets on the {10–10} and {11–20} planes. Other domains ended within the film that formed IDBs on the (0001) and {1–102} planes. The domains were found to grow in clusters and connect at points along the boundary.

Direct observation of ordering in (GaIn) P

1988 ◽  
Vol 3 (3) ◽  
pp. 406-409 ◽  
Author(s):  
S. McKernan ◽  
B. C. De Cooman ◽  
C. B. Carter ◽  
D. P. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Microscope ◽  
Direct Observation ◽  
Vapor Phase ◽  
Growth Conditions ◽  
Dark Field ◽  
Growth Surface ◽  
Organometallic Vapor Phase Epitaxy ◽  
Planar Defects ◽  
Group Iii ◽  
Gaas Substrates

Gax In1 − x Pepilayers grown under a range of growth conditions by organometallic vapor phase epitaxy (OMVPE) on GaAs substrates have been studied in the electron microscope. The results show the presence of an ordering of the group III sublattice parallel to some of the {111} planes. Dark-field images directly reveal ordered domains of different orientations that appear not to be perfect, but contain many planar defects parallel to the growth surface.

Overlapping Shockley/Frank Faults in 4H-SiC PiN Diodes

2006 ◽  
Vol 527-529 ◽  
pp. 383-386 ◽  
Author(s):  
Mark E. Twigg ◽  
Robert E. Stahlbush ◽  
Peter A. Losee ◽  
Can Hua Li ◽  
I. Bhat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Light Emission ◽  
Stacking Faults ◽  
Dark Field ◽  
Pin Diodes ◽  
Plan View ◽  
Planar Defects ◽  
Burgers Vector ◽  
Partial Dislocations ◽  
Transmission Electron

Using light emission imaging (LEI), we have determined that not all planar defects in 4H-SiC PiN diodes expand in response to bias. Accordingly, plan-view transmission electron microscopy (TEM) observations of these diodes indicate that these static planar defects are different in structure from the mobile stacking faults (SFs) that have been previously observed in 4H-SiC PiN diodes. Bright and dark field TEM observations reveal that such planar defects are bounded by partial dislocations, and that the SFs associated with these partials display both Frank and Shockley character. That is, the Burgers vector of such partial dislocations is 1/12<4-403>. For sessile Frank partial dislocations, glide is severely constrained by the need to inject either atoms or vacancies into the expanding faulted layer. Furthermore, these overlapping SFs are seen to be fundamentally different from other planar defects found in 4H-SiC.

Defect and Dopant Control During Silicon Epitaxy Using B and Ge

1987 ◽  
Vol 104 ◽  
Author(s):  
R. R. Kola ◽  
J. B. Posthill ◽  
A. S. M. Salih ◽  
G. A. Rozgonyi ◽  
K. E. Bean ◽  
...  
Keyword(s):  
High Speed ◽  
Maximum Yield ◽  
Dark Field ◽  
Electrical Performance ◽  
Epitaxial Layers ◽  
Threading Dislocation ◽  
Epitaxial Silicon ◽  
Cross Sectional ◽  
Plan View ◽  
Co Doped

ABSTRACTThe control of dopants, impurities and defects for VLSI of silicon integrated circuits requires a complex set of crystal and processing conditions to be satisfied simultaneously. In order to achieve the maximum yield and highest level of electrical performance for a given device design, we have manipulated the lattice constant and boron doping levels in CVD epitaxial silicon layers co-doped with germanium. By adjusting the ratios of germane and diborane in a dichlorosilane/hydrogen CVD reactor we have obtained buried high conducting layers which are strain-free and lattice matched to the Si substrate. Degenerate boron and boron and germanium codoped epitaxial layers on (100) p-type silicon substrates were investigated. Solubility, electrical activity limits and defect structure of boron in strained and strain-free silicon epitaxial layers were investigated by spreading resistance, SIMS profiling, X-ray and transmission electron microscopy techniques. Bright field and weak-beam dark field imaging of cross-sectional and plan-view specimens were used to confirm the presence or absence of precipitates and threading dislocations. A model has been proposed to describe the mechanism of threading dislocation formation in heavily boron-doped layers. We are now in a position to strategically locate co-doped Si(B, Ge) p++ layers as recombination zones or buried field plates to suit the needs of MOS latchup control, high speed and radiation hard devices, as well as the needs of defect free p++ etch stops for thin membranes and three-dimensional silicon structures.

SURFACE TRANSMISSION ELECTRON MICROSCOPY ON STRUCTURES WITH TRUNCATION

1997 ◽  
Vol 04 (04) ◽  
pp. 687-694 ◽  
Author(s):  
KUNIO TAKAYANAGI ◽  
YOSHITAKA NAITOH ◽  
YOSHIFUMI OSHIMA ◽  
MASANORI MITOME
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Dark Field ◽  
Scanning Tunneling ◽  
Plan View ◽  
Step Motion ◽  
Dark Field Imaging ◽  
Surface Steps ◽  
Transmission Electron

Surface transmission electron microscopy (TEM) has been used to reveal surface steps and structures by bright and dark field imaging, and high resolution plan view and/or profile view imaging. Dynamic processes on surfaces, such as step motion, surface phase transitions and film growths, are visualized by a TV system attached to the electron microscope. Atom positions can precisely be detected by convergent beam illumination (CBI) of high resolution surface TEM. Imaging of the atomic positions of surfaces with truncation is briefly reviewed in this paper, with recent development of a TEM–STM (scanning tunneling microscope) system.

Si(111)-(5x2) Au structure from off-axis high-resolution Transmission Electron Microscopy

1994 ◽  
Vol 52 ◽  
pp. 762-763
Author(s):  
R. Plass ◽  
L. D. Marks
Keyword(s):  
High Resolution ◽  
Semiconductor Device ◽  
Dark Field ◽  
X Ray Diffraction ◽  
Plan View ◽  
Flat Surfaces ◽  
Dark Field Imaging ◽  
Semiconductor Interfaces ◽  
Transmission Electron ◽  
Field Imaging

Although metal semiconductor interfaces play a major role in semiconductor device performance the basic understanding of the atomic structure of many of these interfaces has been elusive. The submonolayer of gold on silicon (111) system is of special interest as it displays several different surface structures depending on gold coverage and temperature. Substantial light has been shed on one of these structures, the 5×2 present between .1 and .5 gold monolayers, in recent x-ray diffraction and high resolution STM studies, yet the placement of the gold atoms remains unclear. We present here a solution for this structure found using off-axis plan view HREM and digital image restoration in combination with more conventional bright-field, dark-field imaging and diffraction techniques.Instrumental details related to this experiment have been reviewed by Bonevich and Marks. Si 111 oriented TEM samples with clean, fairly flat surfaces were prepared using Ar+ ion sputter/electron beam annealing cycles.

A Study of Defects in Ordered Ternary Semiconductor Epilayers

1988 ◽  
Vol 130 ◽  
Author(s):  
S. McKernan ◽  
C. B. Carter ◽  
D. P. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Microscope ◽  
Stacking Faults ◽  
Dark Field ◽  
Growth Surface ◽  
Ordered Structure ◽  
Planar Defects ◽  
Gaas Substrates ◽  
Surface Models ◽  
Ternary Semiconductor ◽  
Very High

AbstractOrdered GaxIn1-xP epilayers grown on GaAs substrates have been studied in the electron microscope. Dark-field images and high-resolution micrographs have directly revealed the presence of an ordering of the Ga and In (111) planes. Several different planar defects have been identified in the ordered structure. There is a very high density of faults parallel to the (001) growth surface. Models for these faults have been constructed in terms of stacking faults and twin boundaries in the ordered structure. Other flat planar defects which occur approximately parallel to (111) and (111) planes can also be described in these terms.

Origin of the defect structures in oxygen-implanted silicon-on-insulator material

1993 ◽  
Vol 51 ◽  
pp. 1108-1109
Author(s):  
D. Venables ◽  
S.J. Krause ◽  
J.D. Lee ◽  
J.C. Park ◽  
P. Roitman
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Silicon Layer ◽  
Dark Field ◽  
Silicon On Insulator ◽  
High Dose ◽  
Defect Structures ◽  
Plan View ◽  
High Temperature Anneal ◽  
Single Oxygen

Silicon-on-insulator material fabricated by high-dose oxygen implantation (known as SIMOX) has been used for high speed and radiation hard devices and is under consideration for use in low power applications. However, a continuing problem has been crystalline defects in the top silicon layer. SIMOX is fabricated by two distinct methods: a single oxygen implant to a dose of 1.8×l018 cm-2 followed by a high-temperature anneal (≥1300°C, 4-6 hr) or by multiple lower dose implants (∼6×l017 cm-2) with high-temperature anneals after each implant. To date, there has been no systematic comparison of the defect structures produced by these two fabrication methods. Therefore, we have compared the defect structure and densities in multiple vs. single implant wafers. In this paper we describe the origin and characteristics of the defect structures in SIMOX and show how their densities are controlled by the processing method and conditions.Silicon (100) wafers were implanted in a high current implanter at ∼620°C to doses of 1.8×l018 or 0.6/0.6/0.6×l018 cm-2 and annealed at 1325°C, 4 hr in 0.5% or 5% O2 in Ar. Cross-section (XTEM) and plan-view (PTEM) samples were studied with bright field and weak beam dark field techniques in a transmission electron microscope operating at 200 keV.

A Preparation of High Resolution Standards for Electron Microscopy. Part II

1971 ◽  
Vol 29 ◽  
pp. 160-161
Author(s):  
Akira Tanaka ◽  
David F. Harling
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Carbon Black ◽  
Single Crystal ◽  
Dark Field ◽  
Graphitized Carbon Black ◽  
Graphitized Carbon ◽  
Dark Field Imaging ◽  
Crystal Films ◽  
Micro Holes

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.

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