Characterization of Er/O-doped Si-LEDs with Low Thermal Quenching

2005 ◽  
Vol 866 ◽  
Author(s):  
A. Karim ◽  
W.-X. Ni ◽  
A. Elfving ◽  
P.O.Å. Persson ◽  
G.V. Hansson
Keyword(s):  
Temperature Dependence ◽  
Reverse Bias ◽  
Thermal Quenching ◽  
Constant Current ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Low Energy Electrons ◽  
Higher Temperature ◽  
Electron Emitters

AbstractElectroluminescence studies of MBE-grown Er/O-doped Si-diodes at reverse bias have been done. For some devices there is much reduced thermal quenching of the emission at 1.54 νm. There are examples where the temperature dependence is abnormal in that the intensity for a constant current even increases with temperature up to e.g. 80 °C. These devices have been studied with cross-sectional transmission electron microscopy to see the microstructure of the Er/O-doped layers as well as the B-doped SiGe-layers that are used as electron emitters during reverse bias. Although there are defects in the layers there is no evidence for large thick precipitates of SiO2. While reduced thermal quenching often is attributed to having the Er-ions within SiO2 layers, this is not the case for our structures as evidenced by our TEM-studies. The origin of the abnormal temperature dependence is attributed to the two mechanisms of breakdown in the reverse-biased diodes. At low temperature the breakdown current is mainly due to avalanche resulting in low-energy electrons and holes that quenches the intensity by Auger deexcitation of the Er-ions. At higher temperature the breakdown current is mainly phonon-assisted tunneling which results in a more efficient pumping with less de-excitation of the Er-ions. Finally at the highest temperatures the thermal quenching sets in corresponding to an activation energy of 125 meV, which is slightly lower than 150 meV that has been reported in other studies.

Comparison of Ion-Milling Techniques For Cross-Sectional TEM of Semiconductors

1985 ◽  
Vol 43 ◽  
pp. 166-167
Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook
Keyword(s):  
Analytical Techniques ◽  
Sample Surface ◽  
Ion Milling ◽  
Cross Sectional ◽  
Reliable Technique ◽  
Near Surface ◽  
Transmission Electron ◽  
Thin Region ◽  
Transient Thermal

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

High-resolution transmission electron microscopic study of highly oxygen doped silicon layer

1989 ◽  
Vol 47 ◽  
pp. 692-693
Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi
Keyword(s):  
High Resolution ◽  
Oxygen Concentration ◽  
Silicon Layer ◽  
Detailed Structure ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Doped Silicon ◽  
Argon Ion

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.

New Pathways to Heteroepitaxial GaN by Inorganic CVD Synthesis and Characterization of Related Ga-C-N Novel Systems

1996 ◽  
Vol 449 ◽  
Author(s):  
J. Kouvetakis ◽  
M. O’Keeffe ◽  
Louis Brouseau ◽  
J. McMurran ◽  
Darrick Williams ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Columnar Growth ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Single Source Precursor ◽  
Cvd Synthesis ◽  
Oriented Films ◽  
Cubic Structure

ABSTRACTWe describe the development of a new deposition method for thin oriented films of GaN on basal plane sapphire using an exclusively inorganic single-source precursor free of carbon and hydrogen, Cl2GaN3. The films have been characterized by Rutherford backscattering spectroscopy (RBS) and cross sectional transmission electron microscopy (TEM) for composition morphology and structure. RBS analysis confirmed stoichiometric GaN and TEM observations of the highly conformal films revealed heteroepitaxial columnar growth of crystalline wurrtzite material on sapphire. Auger and RBS oxygen and carbon resonance profiles indicated that the films were pure and highly homogeneous. We also report the reactions of Cl2GaN3 with organometallic nitriles to yield a crystalline, novel gallium carbon nitride of composition GaC3N3. Quantitative X-ray powder diffraction has been used to refine the cubic structure of this material which consists of Ga atoms octahedrally surrounded by on the average three C and three N atoms. The structurally analogous LiGaC4N4 phase has also been prepared and characterized.

Characterization of Structure and Mechanical Properties of MoSi2-SiC Nanolayer Composites

1993 ◽  
Vol 322 ◽  
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell
Keyword(s):  
Mechanical Properties ◽  
Structural Changes ◽  
Crystallization Process ◽  
Mechanical Response ◽  
Cross Sectional ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Layer Structures ◽  
Amorphous Structures

AbstractA systematic study of the structure-mechanical properties relationship is reported for MoSi2-SiC nanolayer composites. Alternating layers of MoSi2 and SiC were synthesized by DCmagnetron and if-diode sputtering, respectively. Cross-sectional transmission electron microscopy was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures. Nanoindentation was employed to characterize the mechanical response as a function of the structural changes. As-sputtered material exhibits amorphous structures in both types of layers and has a hardness of 11GPa and a modulus of 217GPa. Subsequent heat treatment induces crystallization of MoSi2 to form the C40 structure at 500°C and SiC to form the a structure at 700°C. The crystallization process is directly responsible for the hardness and modulus increase in the multilayers. A hardness of 24GPa and a modulus of 340GPa can be achieved through crystallizing both MoSi2 and SiC layers. Annealing at 900°C for 2h causes the transformation of MoSi2 into the Cllb structure, as well as spheroidization of the layering to form a nanocrystalline equiaxed microstructure. A slight degradation in hardness but not in modulus is observed accompanying the layer break-down.

Characterization of Electrodeposited Cobalt/Platinum(Ill) Ultrathin Films and Multilayers

1995 ◽  
Vol 382 ◽  
Author(s):  
Y. Jyoko ◽  
S. Kashiwabara ◽  
Y. Hayashi
Keyword(s):  
Electron Microscopy ◽  
Ultrathin Films ◽  
Photoelectron Spectroscopy ◽  
Multilayered Structure ◽  
Cross Sectional ◽  
Composition Modulation ◽  
Potential Control ◽  
Transmission Electron ◽  
Reflection Electron Microscopy

ABSTRACTReflection electron microscopy (REM) studies of Co electrodeposition on Pt(111) singlecrystal surfaces under potential control have revealed a heteroepitaxial and simultaneous multinuclear multilayer growth in a range from several up to some ten monolayer coverages at room temperature. This growth process has been dependent upon the crystallization overpotential during electrodeposition. REM observations have also suggested the formation of an ordered CoPt3 alloy at the interface between the Pt/Co ultrathin bilayers grown epitaxially on Pt(111) surfaces. Auger and photoelectron spectroscopy experiments on the Pt/Co/Pt(111) system have confirmed a limited interdiffusion or interfacial alloying below the Pt overlayer leading to an induced magnetic moment on the Pt atoms. The Pt/Co interface exhibits electronic interface states of mainly Pt-5d character. Cross-sectional transmission electron microscopy (TEM) observations have provided the first direct experimental evidence for composition modulation across successive layers in a Pt/Co nanometer-multilayered structure prepared by electrodeposition.

Characterization of Polysilicon Thin Films by Variable Angle Spectroscopic Ellipsometry

1990 ◽  
Vol 182 ◽  
Author(s):  
Yi-Ming Xiong ◽  
Paul G. Snyder ◽  
John A. Woollam ◽  
Eric R. Krosche ◽  
Yale Strausser
Keyword(s):  
Electron Microscopy ◽  
Spectroscopic Ellipsometry ◽  
Multilayer Structures ◽  
Cross Sectional ◽  
Variable Angle ◽  
Transmission Electron ◽  
Polysilicon Layer ◽  
Variable Angle Spectroscopic Ellipsometry ◽  
Thickness Measurements

AbstractVariable angle spectroscopic ellipsometry was used to characterize polysilicon multilayer structures. Five different multilayer wafers, each containing a polysilicon layer, were studied. Layer thicknesses and compositions were determined at several locations across each wafer. The thickness measurements obtained by ellipsometry are compared with those determined from cross-sectional transmission electron microscopy (XTEM).

Interpretation of Sudden Failures in Pump Laser Diodes

1997 ◽  
Author(s):  
A. Bonfiglió ◽  
M. Vanzi ◽  
M. B. Casu ◽  
F. Magistrali ◽  
M. Maini ◽  
...  
Keyword(s):  
Failure Modes ◽  
Optical Power ◽  
Constant Current ◽  
Recombination Site ◽  
Cross Sectional ◽  
Native Defects ◽  
Defect Growth ◽  
Pump Lasers ◽  
Defect Reaction

Abstract The occurrence of sudden failures has been reported for 980 nm SL SQW InGaAs pump lasers. The post-mortem analysis reveals failure modes that are consistent with the formation of defects at the active area. The problem calls for two separate efforts: monitoring the degradation at suitable time resolution and structural characterization of defects. This article reports about the optical power and overall voltage monitoring results during a constant current lifetest, in which "sudden failures" switched off the lasers in a few hours, after 1500 hours of regular life, and about their interpretation based on TEM cross-sectional images across an EBIC-detected high recombination site. The hypothesis that Recombination Enhanced Defect Reaction (REDR) is a suitable mechanism for defect growth in forward biased GaAs-based diodes is proposed and discussed that REDR is the origin of the observed sudden failures, starting from native defects located in "cool" regions.

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