Monolithic Integration of III-V Microcavity Leds on Silicon Drivers using Conformal Epitaxy

1998 ◽  
Vol 535 ◽  
Author(s):  
B. Gérard ◽  
X. Marcadet ◽  
P. Etienne ◽  
D. Pribat ◽  
D. Friedrich ◽  
...  
Keyword(s):  
Cmos Technology ◽  
High Crystalline Quality ◽  
Growth Technique ◽  
Si Substrates ◽  
Active Structures ◽  
Gaas Substrates ◽  
Low Dislocation Density ◽  
Dislocation Densities ◽  
The Impact

AbstractConformal epitaxy is an epitaxial growth technique capable of yielding low dislocation density III-V films on Silicon. In this technique, the growth of the III-V material occurs parallel to the silicon substrate, from the edge of a previously deposited III-V seed, the vertical growth being stopped by an overhanging capping layer. As an example, conformal GaAs layers on Silicon, presenting dislocation densities below 105cm−2, have been obtained using selective vapor phase epitaxy. These layers have then been used as high quality GaAs on Si substrates for subsequent vertical MBE regrowth of active structures. In this paper, we report on the integration of surface-emitting microcavity LEDs with their silicon drivers using this conformal growth technique. The global technology concept and the design of the active structures are first presented. The compatibility of the conformal growth technique with CMOS technology is then checked: the impact of the integration process on the performances of the drivers is for example quantified. Characterisations of the high crystalline quality of the conformal layers and of the LEDs structures grown on it are then shown. The electro-optical characteristics of the LEDs on Si are finally compared to those of reference LEDs on GaAs substrates in order to prove the efficiency of the integration procedure.

Heteroepitaxy and Characterization of Low-Dislocation-Density GaN on Periodically Grooved Substrates

2000 ◽  
Vol 639 ◽  
Author(s):  
T. Detchprohm ◽  
M. Yano ◽  
R. Nakamura ◽  
S. Sano ◽  
S. Mochiduki ◽  
...  
Keyword(s):  
Dislocation Density ◽  
New Method ◽  
Growth Technique ◽  
New Approach ◽  
Density Area ◽  
Low Dislocation Density ◽  
Dislocation Densities ◽  
Movpe Growth

ABSTRACTWe have developed a new method to prepare low-dislocation-density GaN by using periodically grooved substrates in a conventional MOVPE growth technique. This new approach was demonstrated for GaN grown on periodically grooved α-Al2O3(0001), 6H-SiC(0001)Si and Si(111) substrates. Dislocation densities were 2×107 cm−2 in low-dislocation-density area.

Reduction of Dislocations in the Bulk Growth of SiC Crystals

2006 ◽  
Vol 527-529 ◽  
pp. 3-8 ◽  
Author(s):  
Daisuke Nakamura
Keyword(s):  
Dislocation Density ◽  
Growth Process ◽  
Large Diameter ◽  
Device Performance ◽  
Etch Pit Density ◽  
Bulk Growth ◽  
Etch Pit ◽  
Low Dislocation Density ◽  
The Impact

Recent reports on the impact of elementary dislocations on device performance and reliability suggest not only micropipe defects but also dislocations should be reduced or eliminated perfectly. This paper presents bulk growth process for reduction of the dislocations, and quality of the crystals grown by the process. Etch pit density of the best crystals grown by the process was lower by three orders of magnitude than that of conventional crystals. Moreover, large diameter crystals (>2”) with low dislocation density were successfully grown by the process.

MBE Growth and Characterization of CdTe, ZnTe Epilayers and CdTe/ZnCdTe Superlattices on GaAs Substrates

1992 ◽  
Vol 263 ◽  
Author(s):  
A.E. Milokhin ◽  
I.E. Trofimov ◽  
M.V. Petrov ◽  
F.F. Balakirev ◽  
V.D. Kuzmin ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Buffer Layer ◽  
Lattice Constant ◽  
Strong Influence ◽  
High Crystalline Quality ◽  
Mbe Growth ◽  
X Ray ◽  
Gaas Substrates

Semiconductor heterostuctures ZnxCd1−xTe/CdTe were found to be of interest recently due to their potential practical usage. The reason for this is the beautiful variety of electrical heterostucture properties which arise from the strong influence of elastic deformation distribution. Thin epilayer films and superlattices ZnxCd1−xTe/CdTe were prepared on GaAs semi-isolator substrates by MBE technology with RHEED oscillation measurements of the deposited layers. X-ray measurements have shown high crystalline quality of the samples.We have performed Raman scattering studies of ZnxZnxCd1−xTe/CdTe structures. The data obtained were interpreted as a proff of the pseudomorphous growth model. That is, ZnxCd1−xTe/CdTe SLS keeps the lattice constant of the buffer layer.

Growth and Fundamental Properties of SiGe Single Crystal

2010 ◽  
Vol 129-131 ◽  
pp. 139-142
Author(s):  
Xin Huan Niu ◽  
Bai Mei Tan ◽  
Xiao Hong Zhao ◽  
Wei Lian Zhang
Keyword(s):  
Single Crystal ◽  
Silicon Germanium ◽  
Wave Number ◽  
Longitudinal Distribution ◽  
Bulk Single Crystal ◽  
Growth Technique ◽  
Fundamental Properties ◽  
Spectral Graph ◽  
Low Dislocation Density

Silicon-Germanium (SiGe) single crystal is a fully miscible solid solution with diamond-base, and has attracted keen interest as material for applications such as microelectronic and optoelectronic devices. Consequently, there is a need for SiGe crystals of low dislocation density and large dimensions. In this study, the growth mechanism and methods of SiGe bulk single crystal were described and the PMCZ method made by ourselves was analyzed. The properties of PMCZ SiGe single crystal with different Ge concentrations were discussed. The result shows that the longitudinal distribution homogeneity of impurity Ge was improved on the effect of magnetic field; with Ge concentration creasing, oxygen concentration in SiGe crystals was decreased, and the crystals mechanical strength faded up; with Ge-doped increasing, there appears new absorption peak near 710cm-1and 800cm-1 wave number in Si FTIR absorption spectral graph. From the results, it can be found that with improving the growth technique and increasing Ge concentration, the quality of SiGe single crystal will be improved effectively.

Laser Enhanced Selective Epitaxy of ιii-V Compounds

1987 ◽  
Vol 101 ◽  
Author(s):  
N.H. Karam ◽  
H. Liu ◽  
I. Yoshida ◽  
T. Katsuyama ◽  
S.M. Bedair ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Atomic Layer ◽  
Growth Conditions ◽  
Direct Writing ◽  
Growth Technique ◽  
X Ray ◽  
Selective Epitaxial Growth ◽  
Gaas Substrates ◽  
Ion Laser

ABSTRACTSelective epitaxial growth of III-V compounds based on GaAs has been achieved using Ar+ ion laser assisted chemical vapor deposition (LCVD) on GaAs substrates. The growth rate, at carefully selected growth conditions, can be controlled to a few Å/s at bias temperatures as low as 250°C by conventional LCVD multi-scan technique. Typical Gaussian thickness profiles are achieved by this growth technique. On the other hand, flat top thickness profiles are achieved with direct writing of GaAs mono-layers by laser assisted atomic layer epitaxy (LALE). X-ray topography is demonstrated as a powerful tool for characterizing the grown films and photoluminescence shows that the quality of the grown films are comparable with those grown by conventional MOCVD or ALE.

The Study of Flower-Shaped Structure Dislocation in 4 Inch Germanium Single Crystal

2011 ◽  
Vol 685 ◽  
pp. 141-146 ◽  
Author(s):  
Miao Miao Li ◽  
Xiao Ping Su ◽  
De Shen Feng ◽  
Jian Long Zuo ◽  
Nan Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Dislocation Density ◽  
Single Crystal ◽  
Single Crystals ◽  
Czochralski Method ◽  
Structure Defects ◽  
Germanium Single Crystal ◽  
Low Dislocation Density ◽  
Dislocation Densities

As the key component of single junction GaAs/Ge solar cells and GaAs/Ge solar cells, the quality of germanium single crystal affects the properties of space solar cell directly. The dislocation of germanium single crystals is the main impact factor on solar cells efficiency. Through measuring dislocation densities in the different positions of 4 inch <100> germanium single crystals produced by Czochralski method, we found that flower-shaped structure dislocations pattern was mainly caused by the inclusions. This paper briefly analyzed dislocations produced by inclusions, chemical etching pits method. SEM and EDS measurement methods were also employed to study the flower-shaped structure defects. A germanium single crystal with low dislocation density was obtained and the special defects were almost eliminated. The germanium single crystal with low dislocation density (PV) was obtained, which could meet the requirement of the GaAs/Ge solar cells.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Self-Compassion and Quality of Life in Adults Who Stutter

2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd
Keyword(s):  
Quality Of Life ◽  
Social Connectedness ◽  
The Self ◽  
Future Research ◽  
Self Compassion ◽  
Adults Who Stutter ◽  
And Gender ◽  
Relationship Of ◽  
The Impact

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.

Surgery for Lung Cancer and the Consequences for the Swallow

2016 ◽  
Vol 1 (13) ◽  
pp. 162-168
Author(s):  
Pippa Hales ◽  
Corinne Mossey-Gaston
Keyword(s):  
Lung Cancer ◽  
Treatment Options ◽  
Vocal Cord Palsy ◽  
Subsequent Treatment ◽  
Physiological Reserve ◽  
Palliative Phase ◽  
And Function ◽  
The Impact ◽  
Swallow Function

Lung cancer is one of the most commonly diagnosed cancers across Northern America and Europe. Treatment options offered are dependent on the type of cancer, the location of the tumor, the staging, and the overall health of the person. When surgery for lung cancer is offered, difficulty swallowing is a potential complication that can have several influencing factors. Surgical interaction with the recurrent laryngeal nerve (RLN) can lead to unilateral vocal cord palsy, altering swallow function and safety. Understanding whether the RLN has been preserved, damaged, or sacrificed is integral to understanding the effect on the swallow and the subsequent treatment options available. There is also the risk of post-surgical reduction of physiological reserve, which can reduce the strength and function of the swallow in addition to any surgery specific complications. As lung cancer has a limited prognosis, the clinician must also factor in the palliative phase, as this can further increase the burden of an already compromised swallow. By understanding the surgery and the implications this may have for the swallow, there is the potential to reduce the impact of post-surgical complications and so improve quality of life (QOL) for people with lung cancer.

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