Ion Damage Studies in GaAs/Al0.6Ga0.4As/GaAs Heterostructures

1993 ◽  
Vol 316 ◽  
Author(s):  
B.A. Turkot ◽  
D.V. Forbes ◽  
H. Xiao ◽  
I.M. Robertson ◽  
J.J. Coleman ◽  
...  
Keyword(s):  
Room Temperature ◽  
Defect Density ◽  
Ion Irradiation ◽  
Amorphous Layer ◽  
Damage Distribution ◽  
Cross Sectional ◽  
Bottom Interface ◽  
Damage Structure ◽  
High Resolution Tem ◽  
Degree Of Recovery

ABSTRACTThe development of the damage structure produced in (100) GaAs/Al0.6Ga0.4As/GaAs by 1 MeV Kr+ ion irradiation at 77 and 293 K has been investigated by RBS channeling and cross-sectional high-resolution TEM techniques. Following an implantation to a dose of 1014 ions cm-2 at 77 K, RBS channeling spectra indicate that the Al0.6Ga0.4 layer contained a high defect density and was possibly amorphous. Warming to room temperature resulted in a change in the channeling spectrum, which indicated that the damage in the Al0.6Ga0.4As layer had partially recovered. The degree of recovery was greatest at the GaAs/ Al0.6Ga0.4As interface, and decreased with increasing depth. TEM observations show the damage in the Al0.6Ga0.4As to be comprised of planar defects, the density of which increases with depth, and an amorphous layer at the bottom interface. This difference in the damage distribution is consistent with the asymmetry in the channeling spectrum. A model based on the depth variation of cascade density is proposed to account for the observations.

Application of Low Temperature InP Wafer Bonding Towards Optical Add/Drop Multiplexer Realization

2004 ◽  
Vol 829 ◽  
Author(s):  
J. Arokiaraj ◽  
S. Vicknesh ◽  
A. Ramam
Keyword(s):  
Indium Phosphide ◽  
Wafer Bonding ◽  
Room Temperature ◽  
Amorphous Layer ◽  
Cross Sectional ◽  
Current Voltage ◽  
High Resolution Tem ◽  
Higher Temperature ◽  
Current Voltage Characteristics ◽  
Bonding Method

AbstractA method to bond directly Indium Phosphide to Indium phosphide at low temperatures has been realized. The treatment of wafers in HF and oxygen plasma exposure prior to bonding is helpful in activating the surface of the wafers at room temperature. This surface activation is useful to bond the wafers at room temperature. Further higher temperature (220°C) treatment with pressure, aided in the completion of the wafer bonding process. The interface of the bonded structures revealed a very thin amorphous layer of oxide when examined under high resolution TEM. Cross-sectional micro Raman measurements revealed signatures corresponding to some disordered associated layer at the interface. Current-Voltage characteristics exhibited ohmic conduction across the interface. The wafer bonding method developed would serve as a useful tool for the fabrication of photonic and optoelectronic devices.

A Method for Site Specific Characterization Using a Dedicated FIB System Combined With an Analyitical TEM

1999 ◽  
Vol 5 (S2) ◽  
pp. 914-915
Author(s):  
T. Kamino ◽  
T. Yaguchi ◽  
H. Matsumoto ◽  
H. Kobayashi ◽  
H. Koike
Keyword(s):  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
System Stability ◽  
Specimen Preparation ◽  
Thin Specimen ◽  
Cross Sectional ◽  
Site Specific ◽  
Specimen Holder ◽  
High Resolution Tem

A method for site specific characterization of the materials using a dedicated focused ion beam(FIB) system and an analytical transmission electron microscope (TEM) was developed. Needless to say, in TEM specimen preparation using FIB system, stability of a specimen is quite important. The specimen stage employed in the developed FIB system is the one designed for high resolution TEM, and the specimen drift rate of the stage is less than lnm/min. In addition, FIB-TEM compatible specimen holder which allows milling of a specimen with the FIB system and observation of the specimen with the TEM without re-loading was developed. To obtain thin specimen from the area to be characterized correctly, confirmation of the area before final milling is needed. However, observation of cross sectional view in a FIB system is recommended because it causes damage by Ga ion irradiation. To solve this problem, we used a STEM unit as a viewer of FIB milled specimen.

Flux Dependence of Amorphous Layer Formation and Damage Annealing in Room Temperature Implantation of Boron into Silicon

1993 ◽  
Vol 316 ◽  
Author(s):  
Robert Simonton ◽  
Jinghong Shi ◽  
Ted Boden ◽  
Philippe Maillot ◽  
Larry Larson
Keyword(s):  
Sheet Resistance ◽  
Room Temperature ◽  
Strong Dependence ◽  
Amorphous Layer ◽  
High Flux ◽  
Dislocation Loops ◽  
Layer Formation ◽  
Cross Sectional ◽  
Implantation Temperature ◽  
Beam Currents

ABSTRACTWe implanted <100> silicon 200mm wafers with 20keV 11B+ to a fluence of 5×1015 atoms/ cm2 using beam currents from 1-7mA, which produced flux of about 50-350µA/cm2. The implant temperature of all wafers rose no more than five degrees above room temperature, regardless of flux. Cross sectional TEM images (as-implanted) of the highest flux samples revealed a continuous amorphous layer from the implanted surface to a depth of about 530Å. The high flux and <30°C implantation temperature allowed amorphous layer formation even with this moderate boron fluence, as was suggested by Jones, et.al.1. We observed a strong dependence of as-implanted damage on boron flux, as previously reported by Eisen and Welch2. After 900°C, 20 sec RTA, the highest flux samples had 50% lower sheet resistance than the lowest flux samples, due to better activation, as observed in SRP. When a 1050°C, 15 sec RTA was employed, this sheet resistance and activation dependence on flux disappeared. Cross sectional TEM images revealed that the size and number of the Type II end of range defects , which were centered near the amorphous and crystalline as-implanted interface, in the highest flux samples were smaller than the Type 1 dislocation loops centered about the peak disorder in the lowest flux samples after RTA. SIMS and SRP profiles indicated that transient enhanced diffusion during the 900°C, 20 sec RTA may have been reduced in the highest flux samples. Based on these observations and on previous reports, we conclude that sufficiently high flux during room temperature boron implantation will produce a continuous amorphous layer with doses that are appropriate for p-type source/drain formation. The amorphous layer will produce improved activation and damage annealing behavior in subsequent RTA, particularly as the RTA temperature is reduced.

High-resolution TEM and energy filtering TEM study of interfacial structure and reaction of diamond/Si in chemical vapor deposition

1995 ◽  
Vol 53 ◽  
pp. 272-273
Author(s):  
Fu-Rong Chen ◽  
L. Chang ◽  
C. J. Chen ◽  
T. S. Lin
Keyword(s):  
High Resolution ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Amorphous Layer ◽  
Interfacial Structure ◽  
Cross Sectional ◽  
Energy Filtering ◽  
Processing Step ◽  
Microwave Plasma Cvd ◽  
High Resolution Tem

Diamond film was grown using microwave plasma CVD technique which consists of three steps: carburization, bias and growth . The high resolution TEM (HRTEM) in cross-sectional view has been used to observe the evolution of interfacial structure in each processing step [1]. The chemistry near the interface was characterized with elemental mapping using energy-filtered imaging technique with Gatan imaging Filter (GIF) [2]. At the carburization stage, β-SiC, diamond particles and graphite plates have been observed in an amorphous layer. This amorphous layer was analysized to be carbon by energy filtering technique.As shown in the Fig. 1, β-SiC can form in epitaxial orientation with Si in the following stage of biasing. Graphite was not observed after the bias was applied. At the bias stage there is an interlayer of 6 nm thick between diamond and silicon substrate . From the high resoultion image in Fig. 2 (a), most of the regions of the interlayer are of amorphous characteristics which presents a barrier to identify the elemental compositions.

Enhanced Boron Diffusion in Amorphous Silicon

2004 ◽  
Vol 810 ◽  
Author(s):  
J.M. Jacques ◽  
N. Burbure ◽  
K.S. Jones ◽  
M.E. Law ◽  
L.S. Robertson ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Boron Diffusion ◽  
Cross Sectional ◽  
Enhanced Diffusion ◽  
Transmission Electron ◽  
Variable Angle Spectroscopic Ellipsometry ◽  
Secondary Ion

ABSTRACTIn prior works, we demonstrated the phenomenon of fluorine-enhanced boron diffusion within self-amorphized silicon. Present studies address the process dependencies of low temperature boron motion within ion implanted materials utilizing a germanium amorphization. Silicon wafers were preamorphized with either 60 keV or 80 keV Ge+ at a dose of 1×1015 atoms/cm2. Subsequent 500 eV, 1×1015 atoms/cm211B+ implants, as well as 6 keV F+ implants with doses ranging from 1×1014 atoms/cm2 to 5×1015 atoms/cm2 were also done. Furnace anneals were conducted at 550°C for 10 minutes under an inert N2 ambient. Secondary Ion Mass Spectroscopy (SIMS) was utilized to characterize the occurrence of boron diffusion within amorphous silicon at room temperature, as well as during the Solid Phase Epitaxial Regrowth (SPER) process. Amorphous layer depths were verified through Cross-Sectional Transmission Electron Microscopy (XTEM) and Variable Angle Spectroscopic Ellipsometry (VASE). Boron motion within as-implanted samples is observed at fluorine concentrations greater than 1×1020 atoms/cm3. The magnitude of the boron motion scales with increasing fluorine dose and concentration. During the initial stages of SPER, boron was observed to diffuse irrespective of the co-implanted fluorine dose. Fluorine enhanced diffusion at room temperature does not appear to follow the same process as the enhanced diffusion observed during the regrowth process.

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.

Ion-Irradiation Study of the “Exotic” Mineral Neptunite: LiNa2K(Fe,Mg,Mn)2Ti2Si8O24

1990 ◽  
Vol 201 ◽  
Author(s):  
Ray K. Eby ◽  
L. M. Wang ◽  
G. W. Arnold ◽  
R. C. Ewing
Keyword(s):  
Surface Layer ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Amorphous Layer ◽  
Narrow Region ◽  
Transmission Electron ◽  
Room Temperature Aging ◽  
Transparent Region ◽  
Amorphous Surface ◽  
Temperature Aging

AbstractSingle crystals of the silicate neptunite were irradiated with 600 keV Ar2+ and 1.5 MeV Kr+ and analysed by transmission electron microscopy. Amorphization was observed in a surface layer several hundred angstroms thick following Ar2+ irradiations up to 5.0×l013 Ar/cm2, yet the Ar2+ ions travelled an average of 1/2 μm in depth. The microstructure of the amorphous surface layer depends on the ion fluence, but the amorphous layer thickness remained constant. At the highest fluence, a narrow region below the amorphous layer shows a brittle-to-ductile strain transition, due to tensional volume-expansion of the adjacent ductile amorphous layer. With 1.5 MeV Kr1+, amorphization of the electron transparent region was completed after a fluence of 1.7×l014 Kr+/cm2, and no further damage was observed up to 5.1×1015 Kr+/cm2. However, following a low fluence of 2.0×1011 Kr+/cm2, a single crystal of neptunite became a polycrystalline aggregate (grain size 10 nm) within 7 days of room temperature aging.

Implant Damage in AlGaAs Based Superlattices and Alloys at 77K

1989 ◽  
Vol 147 ◽  
Author(s):  
E. A. Dobisz ◽  
H. Dietrich ◽  
A. W. McCormick ◽  
J. P. Harbison
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layer Thickness ◽  
Room Temperature ◽  
Amorphous Layer ◽  
Current Work ◽  
Cross Sectional ◽  
Bulk Gaas ◽  
Transmission Electron ◽  
Extensive Damage

AbstractPreviously, it was shown that superlattices implanted with Si at 77K, exhibited more extensive damage and uniform compositional mixing upon subsequent annealing than samples implanted at room temperature.[l,2] The current work focuses on the damage in samples implanted with Si at 77K. The study shows that for a given dose, the amount of damage depends upon the layer thickness and the composition. Specimens of bulk GaAs, Al 3Ga. 7As, 7.5 nm GaAs -10 nm Al. 3Ga. 7As superlattice (SL1), 5.5 nm GaAs −3.5 nm AlAs superlattice (SL2), and 8.0 nm GaAs −8.0 nm AlAs superlat-tice (SL3) were implanted at 77K with 100 KeV Si, with doses ranging from 3 × 1013 cm−2 to 1 × 1015 cm−2. The samples were examined by ion channelling and cross sectional transmission electron microscopy (TEM). At 77K and a dose of 1 × 1014 cm−2, the GaAs and SLi showed an amorphous layer, while no damage peak was observed in SL2. The 77K amorphization thresholds of the Al 3Ga. 7As alloy, SL2, and SL3 were 2.5 × 1014 cm−2, 4 × 1014 cm−2, and 1 × 1015 cm−2 respectively. The sharpness of the amorphization threshold varied with the material.

Temperature Effects on ion Irradiation Damage in MgAl2O4 Spinel Single Crystals

1994 ◽  
Vol 373 ◽  
Author(s):  
Ning Yu ◽  
Kurt E. Sickafus ◽  
Michael Nastasi
Keyword(s):  
Amorphous Phase ◽  
Transition Layer ◽  
Ion Irradiation ◽  
Metastable Phase ◽  
High Resolution Electron Microscopy ◽  
Amorphous Layer ◽  
Irradiation Damage ◽  
Cubic Phase ◽  
Epitaxial Relationship ◽  
Cross Sectional

AbstractSingle crystalline samples of magnesium aluminate spinel (MgAl2O4), <100> oriented, were irradiated at 100 K and 670 K with 370-400 keV Xe ions to doses of (1-2)x1016 Xe/cm2. The microstructures of irradiated samples were subsequently examined by cross-sectional transmission electron microscope. A uniform layer of amorphous phase was observed on the surface of spinel irradiated at 100 K. At the end of the damage range underlying the amorphous layer, a disordered transition layer resided on the undamaged substrate. Both high resolution electron microscopy and microdiffraction revealed that the transition layer retained single crystallinity with epitaxial relationship to the underlying substrate. However, the intensity of <220> reflections in the transition layer was significantly weaker than that of the undamaged spinel. No evidence of amorphization was found in the spinel sample irradiated at 670 K to a dose of 2x1016 Xe/cm2. The <220> reflections exhibit only limited diminution in the heavily damaged region. The observation of reduced intensity of <220> reflections or absent reflections suggests that spinel experiences a structural transition from its original cubic phase (a=0.808 nm) to a new cubic phase (a=0.404 nm). A transition sequence from the original phase to a metastable phase and then to an amorphous phase has been observed. The temperature dependence of metastable and amorphous phase formation has revealed that the accumulation efficiency of cation disorder decreases with increasing irradiation temperature due to the enhancement of interstitial-vacancy recombination.

Damage Evolution in Xe-Ion Irradiated Rutile (TiO2) Single Crystals

1998 ◽  
Vol 540 ◽  
Author(s):  
Fuxin Li ◽  
Ping Lu ◽  
Kurt E. Sickafus ◽  
Caleb R. Evans ◽  
Michael Nastasi
Keyword(s):  
Single Crystals ◽  
Ion Irradiation ◽  
Amorphous Layer ◽  
High Concentration ◽  
Cross Sectional ◽  
Defect Migration ◽  
Ion Channeling ◽  
Projected Range ◽  
Transmission Electron ◽  
Nucleation Sites

AbstractRutile (TiO2) single crystals with (110) orientation were irradiated with 360 keV Xe2+ ions at 300K to fluences ranging from 2×1019 to 1×1020 Xe/m2. Irradiated samples were analyzed using: (1) Rutherford backscattering spectroscopy combined with ion channeling analysis (RBS/C); and (2) cross-sectional transmission electron microscopy (XTEM). Upon irradiation to a fluence of 2×1O19 Xe/m2, the sample thickness penetrated by the implanted ions was observed to consist of three distinct layers: (1) a defect-free layer at the surface (thickness about 12 nm) exhibiting good crystallinity; (2) a second layer with a low density of relatively large- sized defects; and (3) a third layer consisting of a high concentration of small defects. After the fluence was increased to 7×1019 Xe/m2, a buried amorphous layer was visible by XTEM. The thickness of the amorphous layer was found to increase with increasing Xe ion fluence. The location of this buried amorphous layer was found to coincide with the measured peak in the Xe concentration (measured by RBS/C), rather than with the theoretical maXimum in the displacement damage profile. This observation suggests the implanted Xe ions may serve as nucleation sites for the amorphization transformation. The total thickness of the damaged microstructure due to ion irradiation was always found to be much greater than the projected range of the Xe ions. This is likely due to point defect migration under the high stresses induced by ion implantation.

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