Correlation of Void Formation with the Reduction of Carrier Activation and Anomalous Dopant Diffusion in Si-Implanted GaAs

1989 ◽  
Vol 163 ◽  
Author(s):  
Kei-Yu Ko ◽  
Samuel Chen ◽  
S. -Tong Lee ◽  
Longru Zheng ◽  
T.Y. Tan
Keyword(s):  
Carrier Concentration ◽  
Void Formation ◽  
Surface Region ◽  
High Dose ◽  
Near Surface ◽  
Transmission Electron ◽  
Severe Reduction ◽  
Normal Carrier ◽  
Spherical Voids ◽  
Diffusion Profiles

AbstractWe report the study of high-dose Si-implanted GaAs containing doses ranging from 1×1014 to 1×1015 cm-2 and with subsequent anneals at 850°C for 1 hour. At doses ≥ 3×1014 cm-2, a severe reduction of carrier concentration and anomalous Si diffusion are observed in the near-surface region. In the same region, small, near-spherical voids are found by transmission electron microscopy. In contrast, for samples implanted with doses ≤ 1×1014 cm-2, voids are not found, and both normal carrier activation and Si diffusion profiles are observed. The concurrent onset of these three phenomena in the same region in high-dose samples leads us to conclude that the severe reduction of carrier concentration and anomalous Si diffusion are attributable to the formation of voids.

Ion Synthesis of Colloidal Silver Nanoclusters in the Organic Substrate

1995 ◽  
Vol 392 ◽  
Author(s):  
A. L. Stepanov ◽  
S. N. Abdullin ◽  
R. I. Khaibullin ◽  
V. F. Valeev ◽  
Yu. N. Osin ◽  
...  
Keyword(s):  
Surface Region ◽  
Organic Substrate ◽  
Silver Nanoclusters ◽  
High Dose ◽  
Near Surface ◽  
Organic Systems ◽  
Transmission Electron ◽  
Uv Visible ◽  
Average Size ◽  
Metallic Grains

AbstractHigh-dose ion implantation was used to create silver metallic grains in the epoxy resins The structure and optical properties of Ag/organic systems were investigated by transmission electron microscopy and absorption UV-visible spectroscopy, It was established that silver implantation into the organic substrate produced colloidal nanoclusters in the near-surface region, whose average size and size distribution were function of dose value. The silver nanoclusters give rise to optical absorption at the plasmon wavelength. and maximum absorption was shown to be correlated with filling factors. The d.c. resistivities of irradiated samples were measured in temperature range from 5 to 300 K The observed exp(T0/T)n behaviour of resistivity indicated that synthesized metal particles are separated.

Surface Disordering and Nitrogen Loss in GaN under Ion Bombardment

2000 ◽  
Vol 622 ◽  
Author(s):  
S.O. Kucheyev ◽  
J.S. Williams ◽  
C. Jagadish ◽  
J. Zou ◽  
M. Toth ◽  
...  
Keyword(s):  
Nitrogen Loss ◽  
Surface Region ◽  
Ion Bombardment ◽  
High Dose ◽  
Near Surface ◽  
Lattice Disorder ◽  
Transmission Electron ◽  
Cathodoluminescence Spectroscopy ◽  
Wide Range ◽  
Strong Surface

ABSTRACTThe damage build-up and amorphization behavior in wurtzite GaN films under a wide range of implant conditions are studied by Rutherford backscattering / channeling spectrometry, transmission electron microscopy, and cathodoluminescence spectroscopy. A strong surface peak of lattice disorder, in addition to the expected damage peak in the region of the maximum of nuclear energy loss, has been observed for all implant conditions of this study. Capping of GaN with SiOx and SixNy layers prior to implantation does not eliminate surface disordering. This may suggest that nitrogen loss is not the main reason for the observed enhanced surface disorder, but, rather, the GaN surface acts as a strong sink for migrating point defects. However, pronounced loss of N during ion bombardment is observed for high dose implantation when the near-surface region is amorphized. Moreover, after amorphization, annealing at temperatures above about 400°C leads to complete decomposition of the near-surface layer.

Nanoscale Mechanical Properties of In-Situ Tribofilms Generated from ZDDP and F-ZDDP with and without Antioxidants

2007 ◽  
Vol 7 (12) ◽  
pp. 4378-4390 ◽  
Author(s):  
Anuradha Somayaji ◽  
Ramoun Mourhatch ◽  
Pranesh B. Aswath
Keyword(s):  
Electron Microscopy ◽  
Wear Debris ◽  
Surface Region ◽  
Nucleation And Growth ◽  
Near Surface ◽  
Transmission Electron ◽  
Dialkyl Dithiophosphates ◽  
Wear Tests ◽  
Diphenyl Amine

Tribofilms with thickness ranging from 100–200 nm were developed in-situ during wear tests using a zinc dialkyl dithiophosphates (ZDDP) and fluorinated ZDDP (F-ZDDP). The influence of the antioxidant alkylated diphenyl amine on the formation and properties of these tribofilm is examined. Results indicate that the thickness of the tribofilms formed when F-ZDDP is used is always thicker than the tribofilm formed with ZDDP. In addition, in the presence of antioxidants the tribofilm thickness is increased. The hardness of these tribofilms in the absence of the antioxidants is significantly higher at the near surface region (0–30 nm) when compared to the films formed in the presence of antioxidant. Nanoscratch tests conducted to examine the abrasion resistance of the tribofilms also indicate that the tribofilms formed by F-ZDDP are more resistant to scratch compared to films formed by ZDDP. In the presence of antioxidant, tribofilms formed by F-ZDDP are significantly thicker while both films behave in a similar fashion in nanoscratch tests. Transmission electron microscopy of the wear debris formed during the tests were examined and results indicate the nucleation and growth of nanoparticles of Fe3O4 with an approximate size of 5–10 nm embedded within an otherwise amorphous tribofilm.

Amortization and Recrystallization of 6H-SiC by ion Beam Irradiation

1994 ◽  
Vol 339 ◽  
Author(s):  
V. Heera ◽  
R. Kögler ◽  
W. Skorupa ◽  
J. Stoemenos
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Surface Region ◽  
Ion Beam Irradiation ◽  
Surface Layers ◽  
Near Surface ◽  
Transmission Electron ◽  
Amorphous Surface ◽  
Amorphous Sic

ABSTRACTThe evolution of the damage in the near surface region of single crystalline 6H-SiC generated by 200 keV Ge+ ion implantation at room temperature (RT) was investigated by Rutherford backscattering spectroscopy/chanelling (RBS/C). The threshold dose for amorphization was found to be about 3 · 1014 cm-2, Amorphous surface layers produced with Ge+ ion doses above the threshold were partly annealed by 300 keV Si+ ion beam induced epitaxial crystallization (IBIEC) at a relatively low temperature of 480°C For comparison, temperatures of at least 1450°C are necessary to recrystallize amorphous SiC layers without assisting ion irradiation. The structure and quality of both the amorphous and recrystallized layers were characterized by cross-section transmission electron microscopy (XTEM). Density changes of SiC due to amorphization were measured by step height measurements.

Electrical and Structural Characterization of Boron Implanted Silicon Following Laser Thermal Processing

2002 ◽  
Vol 717 ◽  
Author(s):  
K. A. Gable ◽  
K. S. Jones ◽  
M. E. Law ◽  
L. S. Robertson ◽  
S. Talwar
Keyword(s):  
Melting Temperature ◽  
Thermal Processing ◽  
Laser Annealing ◽  
Substrate Surface ◽  
Surface Region ◽  
Process Window ◽  
Near Surface ◽  
Dopant Activation ◽  
Transmission Electron ◽  
Laser Thermal Processing

AbstractOne alternative to conventional rapid thermal annealing (RTA) of implants for ultra-shallow junction formation is that of laser annealing. Laser thermal processing (LTP) incorporates an excimer pulsed laser capable of melting the near surface region of the silicon (Si) substrate. The melt depth is dependent upon the energy density supplied by the irradiation source and the melting temperature of the substrate surface. A process window associated with this technique is able to produce similar junction depths over a range of energy densities due to the melting temperature depression established with pre-amorphization of the substrate surface prior to dopant incorporation. The process window of germanium (Ge) preamorphized, boron (B) doped Si was investigated. 200 mm (100) n-type Si wafers were preamorphized via 18 keV Ge+ implantation to 1x1015/cm2 and subsequently implanted with 1 keV B+ to doses of 1x1015/cm2, 3x1015/cm2, 6x1015/cm2, and 9x1015/cm2. The wafers were laser annealed from 0.50 J/cm2 to 0.88 J/cm2 using a 308 nm XeCl excimer irradiation source. Transmission electron microscopy (TEM) was used to determine the process window for each implant condition, and correlations between process window translation and impurity concentration were made. Four-point probe quantified dopant activation and subsequent deactivation upon post-LTP furnace annealing.

Using Ion Beams to Modify Nanocrystalline Composites: Co Nanoparticles in Sapphire

2001 ◽  
Vol 703 ◽  
Author(s):  
A. Meldrum ◽  
K.S. Beaty ◽  
M. Lam ◽  
C.W. White ◽  
R.A. Zuhr ◽  
...  
Keyword(s):  
Surface Region ◽  
Amorphous Layer ◽  
Ion Beams ◽  
Near Surface ◽  
Nanocrystalline Composites ◽  
Transmission Electron ◽  
Co Nanoparticles ◽  
20 Nm ◽  
And Control ◽  
Single Crystal Sapphire

ABSTRACTIon implantation and thermal processing were used to create a layer of Co nanoclusters embedded in the near-surface region of single-crystal sapphire. The Co nanoparticles ranged in size from 2-20 nm and were crystallographically aligned with the host sapphire. Specimens were irradiated with Xe and Pt ions, and the microstructural evolution of the nanoclusters was investigated by transmission electron microscopy. With increasing Pt or Xe ion dose, the Co nanoparticles lost their initially excellent faceting, although they remained crystalline. The host Al2O3 became amorphous and the resulting microstructure consisted of a buried amorphous layer containing the still-crystalline Co nanoparticles. EDS mapping and electron diffraction were used to determine the distribution of the implanted species, and the magnetic properties of the composite were measured with a SQUID magnetometer. The results show that ion beams can be applied to modify and control the properties of ferromagnetic nanocomposites, and, combined with lithographic techniques, will find applications in exercising fine-scale spatial control over the properties of magnetic materials.

BIC Formation and Boron Diffusion in Relaxed Si0.8Ge0.2

2004 ◽  
Vol 810 ◽  
Author(s):  
R. T. Crosby ◽  
L. Radic ◽  
K. S. Jones ◽  
M. E. Law ◽  
P.E. Thompson ◽  
...  
Keyword(s):  
Surface Region ◽  
Extended Defects ◽  
Defect Structures ◽  
Boron Diffusion ◽  
Plan View ◽  
Near Surface ◽  
Transmission Electron ◽  
Secondary Ion ◽  
Ion Implanted

ABSTRACTThe relationships between Boron Interstitial Cluster (BIC) evolution and boron diffusion in relaxed Si0.8Ge0.2 have been investigated. Structures were grown by Molecular Beam Epitaxy (MBE) with surface boron wells of variant composition extending 0.25 [.proportional]m into the substrate, as well as boron marker layers positioned 0.50 [.proportional]m below the surface. The boron well concentrations are as follows: 0, 7.5×1018, 1.5×1019, and 5.0×1019 atoms/cm3. The boron marker layers are approximately 3 nm wide and have a peak concentration of 5×1018 atoms/cm3. Samples were ion implanted with 60 keV Si+ at a dose of 1×1014 atoms/cm2 and subsequently annealed at 675°C and 750°C for various times. Plan-view Transmission Electron Microscopy (PTEM) was used to monitor the agglomeration of injected silicon interstitials and the evolution of extended defects in the near surface region. Secondary Ion Mass Spectroscopy (SIMS) concentration profiles facilitated the characterization of boron diffusion behaviors during annealing. Interstitial supersaturation conditions and the resultant defect structures of ion implanted relaxed Si0.8Ge0.2 in both the presence and absence of boron have been characterized.

Defect Pair Formation by Implantation-Induced Stresses in High-Dose Oxygen Implanted Silicon-on-Insulator Material

1993 ◽  
Vol 316 ◽  
Author(s):  
J.D. Lee ◽  
J.C. Park ◽  
D. Venables ◽  
S.J. Krause ◽  
P. Roitman
Keyword(s):  
Defect Density ◽  
Silicon On Insulator ◽  
Surface Strain ◽  
High Dose ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Density Reduction ◽  
Transmission Electron ◽  
Pair Density

ABSTRACTDefect microstructure and the near-surface strain of high-dose oxygen implanted silicon-on-insulator material (SIMOX) were investigated as a function of dose, implant temperature, and annealing temperature by transmission electron microscopy and high resolution x-ray diffraction. Dislocation half loops (DHLs) begin to form by stress assisted climb at a critical stress level due to implantation-induced damage. DHLs evolve into through-thickness defect (TTD) pairs by expansion during annealing. Both DHL and TTD-pair density increase with higher implant dose and lower implant temperature. Possible methods for defect density reduction are suggested based on the results of this study.

Electrical Properties of Epitaxial Silicide-Silicon Interfaces

1985 ◽  
Vol 54 ◽  
Author(s):  
R. T. Tung ◽  
A. F. J. Levi ◽  
J. M. Gibson ◽  
K. K. Ng ◽  
A. Chantre
Keyword(s):  
Fermi Level ◽  
Single Crystal ◽  
Schottky Barrier ◽  
Surface Region ◽  
Ideal Behavior ◽  
Near Surface ◽  
Barrier Heights ◽  
Transmission Electron ◽  
Current Voltage ◽  
P Type

ABSTRACTThe Schottky barrier heights of single crystal NiSi2 layers on Si(111) have been studied by current-voltage, capacitance-voltage and activation energy techniques. Near ideal behavior is found for Schottky barriers grown on substrates cleaned at ∼820°C in ultrahigh vacuum. The Fermi level positions at the interfaces of single crystal type A and type B NiSi2 are shown to differ by ∼0.14 eV. Transmission electron microscopy demonstrated the epitaxial perfection of these suicide layers. At a cleaning temperature of 1050° C, the near surface region of lightly doped n-type Si was converted to p-type. The presence of a p-n junction was directly revealed by spreading resistance measurements and resulted in a high apparent Schottky barrier height (≥0.75 eV) which no longer bears immediate relationship to the interface Fermi level position.

Substrate Surface Effects on the Properties of Sputter-Deposited and Laser-Irradiated Films.

1991 ◽  
Vol 238 ◽  
Author(s):  
A. J. Pedraza ◽  
M. J. Godbole ◽  
L. Romana
Keyword(s):  
Electron Microscopy ◽  
Substrate Surface ◽  
Surface Condition ◽  
Surface Region ◽  
Film Rupture ◽  
Near Surface ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Tunnelling Microscopy ◽  
Sputter Deposited

ABSTRACTSapphire substrates, mechanically polished to an optical finish, were annealed for two days at either 1000°C or 1350°C. The near surface condition of as-polished and of the annealed substrates was analyzed by Rutherford backscattering/channeling (RBS-C) and by scanning electron microscopy/channeling (SEM-C), by transmission electron microscopy (TEM), and by scanning tunnelling microscopy (STM). The polished substrates were found to be RBS-amorphous up to 100 nm, and heavily damaged at larger depths. In agreement with these results, no electron channeling was obtained from polished samples. TEM, however, showed that the damaged region was crystalline, and the only defects detected were microtwins. Both RBS-C and SEM-C analyses revealed that the damage is removed when the sapphire substrates are annealed for 48 hrs. at 1350°C. The condition of the near-surface region, viz., as-polished or annealed, is found to strongly affect the morphology of the laser-irradiated copper films deposited on sapphire substrates. A correlation is found between the threshold for film evaporation and for film rupture upon laser irradiation, both being a function of the substrate condition. It is concluded that the near-surface damaged layer acts as a thermal barrier for heat transport across the substrate.

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