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.

The Effect of Implant Species on the Stability of Ion Implantation Damage

1988 ◽  
Vol 100 ◽  
Author(s):  
K. S. Jones ◽  
S. Prussin ◽  
D. Venables
Keyword(s):  
Solid Solubility ◽  
Chemical Species ◽  
Dislocation Loops ◽  
Cross Sectional ◽  
Plan View ◽  
Damage Category ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Residual Damage ◽  
The Stability

ABSTRACTA systematic study of the effect of the chemical species, implanted into silicon, on the stability of the residual damage has been performed. Plan-view and cross-sectional transmission electron microscopy (TEM) studies show that the stability of the end of range damage (category II) defects upon annealing depends dramatically upon the implant species. This is exemplified by the a comparison of 69Ga and 72Ge implants in which a decrease in the dislocation density by over four orders is noted for 69Ga implants compared to 72Ge implants after identical annealing cycles. Additional comparisons of species with similar atomic masses indicate that this destabilizing influence on the dislocation loops by the implant species is related to exceeding the solid solubility of the implanted species. As a result of this dislocation loop destabilization effect complete elimination of the dislocation loops can be realized after relatively short thermal cycling. Evidence is presented indicating that the precipitates which form upon exceeding the solid solubility (category V defects) are dissolving during this enhanced defect dissolution process.

Structural Defects in Ion Implanted 4H-SiC Epilayers

2000 ◽  
Vol 640 ◽  
Author(s):  
P. O. Å. Persson ◽  
W. Skorupa ◽  
D. Panknin ◽  
A. Kuznetsov ◽  
A. Hallén ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Process ◽  
Ion Concentration ◽  
Electrical Activation ◽  
Structural Defects ◽  
Dislocation Loops ◽  
Transmission Electron ◽  
Residual Damage ◽  
Vacancy Concentrations

ABSTRACTTransmission electron microscopy (TEM) was used to investigate Al, Ar, C and Si ionimplanted 4H-SiC epilayers. After the implantation the samples were thermally annealed for 30 minutes at 1700°C. During the annealing process dislocation loops are formed and the generation of such dislocation loops upon annealing, is investigated with respect to dopant electrical activation, peak ion concentration and calculated interstitial/vacancy concentrations. It is concluded that the dislocation loops are generated as the result of a combination of residual damage and excess interstitials generated in a “plus one” (+1) process.

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.

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.

Cross-Sectional TEM Study Of Phase Separation In Reaction Of Ni-Ta Films With GaAs

1985 ◽  
Vol 54 ◽  
Author(s):  
A. Lahav ◽  
M. Eizenberg ◽  
Y. Komem
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Phase Separation ◽  
Gaas Substrate ◽  
Auger Spectroscopy ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

ABSTRACTThe reaction between Ni60Ta40 amorphous alloy and (001) GaAs was studied by cross-sectional transmission electron microscopy, Auger spectroscopy, and x-ray diffraction. At 400°C formation of Ni GaAs at the interface with GaAs was observed. After heat treatment at 600°C in vacuum a layered structure of TaAs/NiGa/GaAs has been formed. The NiGa layer has epitaxial relations to the GaAs substrate. The vertical phase separation can be explained by opposite diffusion directions of nickel and arsenic atoms.

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.

A study of 2 MeV oxygen implantation to form deeply buried SiO2 layers

1989 ◽  
Vol 4 (5) ◽  
pp. 1227-1232 ◽  
Author(s):  
J. J. Grob ◽  
A. Grob ◽  
P. Thevenin ◽  
P. Siffert ◽  
C. d'Anterroches ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystal Silicon ◽  
Single Step ◽  
Annealing Process ◽  
Dislocation Network ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Distribution Moments ◽  
Best Fit

Oxygen ions were implanted into (100) oriented single crystal Si at energies in the range of 0.6 to 2 MeV at normal and oblique (60°) incidences. Oxygen concentration profiles were measured using the 16O(d, α)14N nuclear reaction for 900 keV deuterons. The experimentally measured oxygen distributions were subsequently fitted to the theoretical profiles calculated assuming the Pearson VI distribution. The distribution moments (Rp, ΔRp, ΔR⊥ skewness, and kurtosis) were deduced as the best fit parameters and compared to the computer simulation results (TRIM 87 and PRAL). Whatever the calculation method, the measured Rp and ΔRp values are close to those predicted by the theory. Deeply buried SiO2 layers were formed using a single step implantation and annealing process. A dose of 1.8 × 1018/cm2 of 2 MeV O+ was implanted into the Si substrate maintained at a temperature of 550 °C. The implanted samples were characterized using the Rutherford backscattering (RBS)/channeling technique and cross-sectional transmission electron microscopy (XTEM). The implanted samples were subsequently annealed at 1350 °C for 4 h in an Ar ambient. The annealing process results in creating a continuous SiO2 layer, 0.4 μm thick below a 1.6 μm thick top single crystal silicon overlayer. The buried SiO2 layer contains the well-known faceted Si inclusions. The density of dislocations within the top Si layer remains lower than the XTEM detection limit of 107/cm2. Between the Si overlayer and the buried SiO2 a layer of faceted longitudinal SiO2 precipitates is present. A localized dislocation network links the precipitates to the buried SiO2 layer.

Shallow Junction Formation in As-Implanted Si by Low-Temperature Rapid Thermal Annealing

1989 ◽  
Vol 147 ◽  
Author(s):  
M. K. El-Ghor ◽  
S. J. Pennycook ◽  
R. A. Zuhr
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Dislocation Loops ◽  
Cross Sectional ◽  
Dopant Activation ◽  
Transmission Electron ◽  
Shallow Junctions ◽  
Surface Image ◽  
Long Time ◽  
Short Time

AbstractShallow junctions were formed in single-crystal Si(100) by implantation of As at energies between 2 and 17.5 keV followed by conventional furnace annealing or by rapid thermal annealing (RTA). Cross-sectional transmission electron microscopy (XTEM) showed that defect-free shallow junctions could be formed at temperatures as low as 700 °C by RTA, with about 60% dopant activation. From a comparison of short-time and long-time annealing, it is proposed that surface image forces are responsible for the efficient removal of end-of-range (EOR) dislocation loops

Temperature Dependence of Damage in Boron-Implanted Silicon

1989 ◽  
Vol 147 ◽  
Author(s):  
G. Ottaviani ◽  
F. Nava ◽  
R. Tonini ◽  
S. Frabboni ◽  
G. F. Cerofolini ◽  
...  
Keyword(s):  
Room Temperature ◽  
Amorphous Layer ◽  
Systematic Investigation ◽  
Vacuum Furnace ◽  
Cross Sectional ◽  
Ion Channeling ◽  
Projected Range ◽  
Transmission Electron ◽  
Boron Implantation ◽  
Residual Damage

AbstractWe have performed a systematic investigation of boron implantation at 30 keV into <100> n-type silicon in the 77 –300 K temperature range and mostly at 9×1015 cm−2 fluence. The analyses have been performed with ion channeling and cross sectional transmission electron microscopy both in as-implanted samples and in samples annealed in vacuum furnace at 500 °C and 850 °C for 30 min. We confirm the impossibility of amorphization at room temperature and the presence of residual damage mainly located at the boron projected range. On the contrary, a continuous amorphous layer can be obtained for implants at 77 K and 193 K; the thickness of the implanted layer is increased by lowering the temperature, at the same time the amorphous-crystalline interface becomes sharper. Sheet resistance measurements performed after isochronal annealing shows an apparent reverse annealing of the dopant only in the sample implanted at 273 K. The striking differences between light and heavy ions observed at room temperature implantation disappears at 77 K and full recovery with no residual damage of the amorphous layer is observed.

The Mechanism of Epitaxial Si-Ge/Si Heterostructure Formation by Wet Oxidation of Amorphous Si-Ge Thin Films

1989 ◽  
Vol 160 ◽  
Author(s):  
S.M. Prokes ◽  
A.K. Rai ◽  
W.E. Carlos
Keyword(s):  
Electron Diffraction ◽  
Solid Phase ◽  
Native Oxide ◽  
Wet Oxidation ◽  
Cross Sectional ◽  
Plan View ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Spin Resonance ◽  
Amorphous Si

AbstractEpitaxial SiGe/Si heterostructures have been formed by wet oxidation from amorphous SiGe films deposited on Si(100). Amorphous SixGe1-x films were deposited at a vacuum of 10-7 Torr. The presence of an initial native oxide precluded solid phase epitaxy under standard annealing conditions, but epitaxy could be achieved by the use of wet oxidation. The samples were oxidized at 900°C for various times and examined in reflection electron diffraction, ellipsometry, cross-sectional and plan-view transmission electron diffraction, and electron spin resonance. The formation of the epitaxial layer and oxide has been examined, and an epitaxial growth model is suggested.

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