THE DEFECT STRUCTURE OF ION-IMPLANTED AlxGa1−xAs/GaAs SUPERLATFICES

1985 ◽  
Vol 56 ◽  
Author(s):  
B.C. DE COOMAN ◽  
C.B. CARTER ◽  
J. RALSTON ◽  
G.W. WICKS ◽  
L.F. EASTMAN
Keyword(s):  
Electron Microscopy ◽  
Point Defects ◽  
Strain Field ◽  
Defect Structure ◽  
Extended Defects ◽  
Cross Sectional ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Residual Damage ◽  
Ion Implanted

AbstractCross-sectional transmission electron microscopy (XTEM) has been used to study the defect structure and intermixing of ion-implanted and annealed AlxGa1−xAs/GaAs superlattices. The results show clearly that the layer intermixing depends on mass and energy of the implanted species and the annealing conditions. The temperature and duration of annealing determines mainly the amount of residual damage. In addition it was observed that in all cases the point-defects agglomeration was influenced by the strain field present at the layer interfaces; extended defects nucleate preferentially in the GaAs layers.

Effect of Dopant Concentrations and Annealing Conditions on the Electrically Active Profiles and Lattice Damage in Al Implanted 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 713-716 ◽  
Author(s):  
Ming Hung Weng ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Salvatore di Franco ◽  
Corrado Bongiorno ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Depth Distribution ◽  
Electrical Activation ◽  
Extended Defects ◽  
Capping Layer ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Lattice Damage ◽  
Reduced Surface

This paper reports on the electrical activation and structural analysis of Al implanted 4H-SiC. The evolution of the implant damage during high temperature (1650 – 1700 °C) annealing results in the presence of extended defects and precipitates, whose density and depth distribution in the implanted sheet was accurately studied for two different ion fluences (1.31014 and 1.31015 cm-2) by transmission electron microscopy. Furthermore, the profiles of electrically active Al were determined by scanning capacitance microscopy. Only a limited electrical activation (10%) was measured for both fluences in the samples annealed without a capping layer. The use of a graphite capping layer to protect the surface during annealing showed a beneficial effect, yielding both a reduced surface roughness and an increased electrical activation (20% for the highest fluence and 30% for the lowest one) with respect to samples annealed without the capping layer.

An analysis of high temperature (1150 °C) furnace annealing of buried oxide wafers formed by ion implantation

1989 ◽  
Vol 4 (1) ◽  
pp. 167-176 ◽  
Author(s):  
S. R. Wilson ◽  
M. E. Burnham ◽  
M. Kottke ◽  
R. P. Lorigan ◽  
S. J. Krause ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ion Implantation ◽  
Structural Changes ◽  
Relative Number ◽  
Silicon On Insulator ◽  
Precipitate Size ◽  
Buried Oxide ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Residual Damage

Silicon-on-insulator films were formed by ion implantation of oxygen and were treated with various annealing cycles at peak temperatures of 1150 °C, 1200 °C, and 1250 °C in a conventional diffusion furnace. The objective of this study was to examine the structural effects on samples with similar oxygen diffusion lengths (from 17 to 33 μm) achieved by annealing at different times and temperatures. The oxygen and silicon distributions, as well as the residual damage and precipitate size and distribution, were measured by Auger electron microscopy, Rutherford backscattering spectroscopy, and transmission electron microscopy. In agreement with previous findings, higher temperatures produced a larger and less defective, “precipitate-free” superficial Si region. The buried oxide layer thickened from 0.33 μm to a maximum of 0.43 μm as some precipitates were incorporated into the buried oxide while others adjacent to the buried oxide grew in size (up to 47 nm) and decreased in relative number. A new result of this systematic study of annealing conditions was that the peak temperature has a greater effect on the morphology and crystal quality of the superficial Si structure than does time at temperature. Structural changes for longer anneals at 1150 °C are not equivalent to shorter anneals at 1250 °C even though the diffusion length of oxygen for these treatments is the same.

INTERMIXING OF ION-IMLANTED AlGaAs/GaAs SUPERLATTICES

1985 ◽  
Vol 56 ◽  
Author(s):  
J. Ralston ◽  
G.W. Wicks ◽  
L.F. Eastman ◽  
L. Rathbun ◽  
B.C. DeCooman ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Auger Spectroscopy ◽  
Annealing Process ◽  
Dislocation Loops ◽  
Dense Network ◽  
Cross Sectional ◽  
The Third ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Residual Damage

AbstractCross-sectional Transmission Electron Microscopy, Sputter-Auger spectroscopy, and Raman spectroscopy have been used to study intermixing and residual damage in annealed ion-implanted Al0.3Ga0.7As/GaAs superlattices. Several implant species were studied Nse, Si, Mg, Be). Three different regions can be distinguished in the annealed ionimplanted superlattice samples. The topmost region contains a dense network of stacking faults and microtwins, residual damage from an implantation-amorphized region which has recrystallized during annealing. In the second region, which is relatively defect-free, either total, or at least appreciable intermixing of the GaAs and Al0.3Ga0.7As layers occurs. For fixed annealing conditions, the degree of intermixing varies with the mass of the implanted species. The third region contains many small dislocation loops which form by the agglomeration of point defects during implantation or the subsequent annealing process. Raman spectroscopy is used to compare the degree of intermixing and residual damage between AlGaAs alloys generated by superlattice disordering and uniform “as-grown” alloys of the same composition which have undergone identical implant and anneal treatments.

Amorphization Mechanism of Si/Ge Superlattices Upon Ion Implantation

1998 ◽  
Vol 540 ◽  
Author(s):  
N.A. Sobolev ◽  
U. Kaiser ◽  
I.I. Khodos ◽  
H. Presting ◽  
U. König
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Implantation ◽  
Point Defects ◽  
Dose Range ◽  
Cross Sectional ◽  
Layer Interaction ◽  
Transmission Electron ◽  
The Cross ◽  
Electron Microdiffraction

AbstractThe damage production in the Si9Ge6 superlattices (SLs) upon implantation of 150 keV Ar+ ions at 300 K was studied my means of the cross-sectional transmission electron microscopy (XTEM) and electron microdiffraction. It was found that the amorphization occurs in a narrow dose range of (1 – 2) × 1014 cm-2 via accumulation of point defects. The conclusion drawn earlier (Mater. Sci. Forum 248-249, 289 (1997)) on the coherent amorphization of the Si and Ge layers in the SLs was confirmed. Possible mechanisms of the layer interaction leading to the observed behavior are discussed.

Lateral Epitaxial Overgrowth of InAs on (100) GaAs Substrates

2002 ◽  
Vol 744 ◽  
Author(s):  
Ganesan Suryanarayanan ◽  
Anish A. Khandekar ◽  
Brian E. Hawkins ◽  
Thomas F. Kuech ◽  
Susan E. Babcock
Keyword(s):  
Electron Microscopy ◽  
Extended Defects ◽  
Double Crystal ◽  
Cross Sectional ◽  
Lateral Epitaxial Overgrowth ◽  
X Ray ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Inas Thin Films

ABSTRACTThe microstructure of epitaxial InAs thin films grown by MOCVD on mask-patterned “LEO” (lateral epitaxial overgrowth) GaAs and on unpatterned GaAs substrates was studied using double-crystal x-ray diffraction, scanning electron microscopy and cross-sectional transmission electron microscopy. This paper describes the improvement in crystal quality (factor of 20 reduction in x-ray rocking curve width), the order of magnitude reduction in dislocation density, and the rearrangement of the remaining extended defects that were observed in the LEO material when compared to the film grown on the unpatterned wafer.

The Formation and Cathodoluminescence Activity of Buffer Layer Edge Dislocations in In0.12Ga0.88As/GaAs Heterostructures

1987 ◽  
Vol 104 ◽  
Author(s):  
E. A. Fitzgerald ◽  
P. D. Kirchner ◽  
G. D. Petit ◽  
J. M. Woodall ◽  
D. G. Ast
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Buffer Layer ◽  
Defect Structure ◽  
Radiative Recombination ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Gaas Buffer Layer ◽  
Edge Dislocations

ABSTRACTThe defect structure of lattice-mismatched one micron In0.12 Ga0.88As epilayers on (001) GaAs was studied with scanning cathodoluminescence (CL) and transmission electron microscopy (TEM). CL examination of the GaAs buffer layer revealed the formation of a segmented network of defects below the interface. Cross-sectional TEM analysis shows that these defects are dislocation half-loops extending from the interface, and the vast majority of these loops lie on the GaAs side of the interface. The dislocations in the GaAs buffer layer were determined to be edge dislocations. Thus, CL images show that edge dislocations in this system are centers for non-radiative recombination. We propose that two 60° dislocations with opposite screw and interface tilt components can glide into the buffer layer to form edge dislocations. Potential energy plots for 60° dislocations near the interface and interacting with interface dislocations supports this model.

Effects Of Damage-Impurity Interaction On Electrical Properties of Se+-Implanted GaAs

1980 ◽  
Vol 2 ◽  
Author(s):  
D. K. Sadana ◽  
J. Washburn ◽  
M. D. Strathman ◽  
G. R. Booker ◽  
M. H. Badawi
Keyword(s):  
Electron Microscopy ◽  
Point Defects ◽  
Secondary Ion Mass Spectrometry ◽  
Concentration Profiles ◽  
Atomic Concentration ◽  
Cross Sectional ◽  
Projected Range ◽  
Transmission Electron ◽  
Impurity Interaction ◽  
Secondary Ion

ABSTRACTInteraction of impurities with the “visible defects” in hot implanted Cr doped semi-insulating (100) GaAs has been investigated. The defects studies were performed using transmission electron microscopy (TEM) and MeV He+ channeled Rutherford backscattering. The defects distribution was obtained by 90° cross-sectional TEM (XTEM). The atomic concentration profiles of Se, and carrier-concentration and mobility profiles were obtained by secondary ion mass spectrometry (SIMS) and Hall measurements in conjunction with chemical stopping, respectively. Comparison of defects, atomic and electrical profiles, showed the formation of secondary defects at and beyond the projected range (Rp), a significant amount of Se+ diffusion beyond Rp, and compensation of electrical carriers caused mainly by the point defects present in hot implanted GaAs.

Application of Cross-Sectional Transmission Electron Microscopy to the Characterization of Ion-Implanted Semiconductors

1985 ◽  
Vol 43 ◽  
pp. 292-295
Author(s):  
T. Sands
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Formation ◽  
Defect Characterization ◽  
Cross Sectional ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Dopant Profile ◽  
The Many

Direct implantation of dopant ions is the most precise method for obtaining a desired dopant profile in a semiconductor substrate. However, in order to achieve satisfactory electrical properties, lattice defects introduced by the energetic dopant ions and by the subsequent annealing process must be confined or eliminated. Because of the many parameters which can be varied during implantation and annealing, it is not generally feasible to survey all conditions. Consequently, the most efficient approach is to understand the mechanisms of defect formation and annealing so that guidelines for choosing a set of implantation/annealing conditions can be determined.Since implantation depths are usually much less than one micron, suitable defect characterization techniques must demonstrate high spatial resolution. Cross-sectional transmission electron microscopy (XTEM) is one such technique. With a resolution (lateral and depth) of ∼0.2nm, the atomic structure of implantation-related defects is accessible.

Cross-Sectional Transmission Electron Microscopy of Defects in Beta Silicon Carbide Thin Films

1985 ◽  
Vol 46 ◽  
Author(s):  
C.H. Carter ◽  
J.A. Edmond ◽  
J.W. Palmour ◽  
J. Ryu ◽  
H.J. Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Silicon Carbide ◽  
Vapor Deposition ◽  
Defect Structure ◽  
Chemical Vapor ◽  
Processing Parameters ◽  
Cross Sectional ◽  
Transmission Electron

AbstractTechniques have been developed at NCSU for fabricating cross-sectional transmission electron microscopy (XTEM) foils from monocrystalline beta silicon carbide thin films grown by chemical vapor deposition. The results of the TEM observations are utilized to discern the efficacy of the various processing parameters in terms of film quality and defect structure as well as oxidation, ion implantation and annealing procedures.

Sign in / Sign up

Export Citation Format

Share Document