Profile broadening of high dose germanium implants into (100) silicon at elevated temperatures due to channeling

1998 ◽  
Vol 83 (7) ◽  
pp. 3565-3573 ◽  
Author(s):  
A. Nejim ◽  
A. P. Knights ◽  
C. Jeynes ◽  
P. G. Coleman ◽  
C. J. Patel
Keyword(s):  
Elevated Temperatures ◽  
High Dose

Effect of Annealing on the Structure of Buried SiO2 Layers Formed By Elevated Temperature High Dose Oxygen Implantation

1985 ◽  
Vol 53 ◽  
Author(s):  
S.J. Krause ◽  
C.O. Jung ◽  
S.R. Wilson ◽  
R.P. Lorigan ◽  
M.E. Burnham
Keyword(s):  
Single Crystal ◽  
Oxide Layer ◽  
Elevated Temperatures ◽  
Superficial Layer ◽  
Silicon On Insulator ◽  
High Dose ◽  
Threading Dislocations ◽  
Heater Temperature ◽  
Buried Oxide ◽  
Structural Differences

ABSTRACTOxygen has been implanted into Si wafers at high doses and elevated temperatures to form a buried SiO2 layer for use in silicon-on-insulator (SOI) structures. Substrate heater temperatures have been varied (300, 400, 450 and 500°C) to determine the effect on the structure of the superficial Si layer through a processing cycle of implantation, annealing, and epitaxial growth. Transmission electron microscopy was used to characterize the structure of the superficial layer. The structure of the samples was examined after implantation, after annealing at 1150°C for 3 hours, and after growth of the epitaxial Si layer. There was a marked effect on the structure of the superficial Si layer due to varying substrate heater temperature during implantation. The single crystal structure of the superficial Si layer was preserved at all implantation temperatures from 300 to 500°C. At the highest heater temperature the superficial Si layer contained larger precipitates and fewer defects than did wafers implanted at lower temperatures. Annealing of the as-implanted wafers significantly reduced structural differences. All wafers had a region of large, amorphous 10 to 50 nm precipitates in the lower two-thirds of the superficial Si layer while in the upper third of the layer there were a few threading dislocations. In wafers implanted at lower temperatures the buried oxide grew at the top surface only. During epitaxial Si growth the buried oxide layer thinned and the precipitate region above and below the oxide layer thickened for all wafers. There were no significant structural differences of the epitaxial Si layer for wafers with different implantation temperatures. The epitaxial layer was high quality single crystal Si and contained a few threading dislocations. Overall, structural differences in the epitaxial Si layer due to differences in implantation temperature were minimal.

The Effects of Low-Energy-Nitrogen-Ion Implantation on the Tribological and Microstructural Characteristics of AISI 304 Stainless Steel

1994 ◽  
Vol 116 (4) ◽  
pp. 870-876 ◽  
Author(s):  
R. Wei ◽  
B. Shogrin ◽  
P. J. Wilbur ◽  
O. Ozturk ◽  
D. L. Williamson ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Elevated Temperatures ◽  
Wear Behavior ◽  
Plasma Nitriding ◽  
Low Energy ◽  
304 Stainless Steel ◽  
High Dose ◽  
Ion Energy ◽  
Wear Resistant ◽  
Nitrogen Ion

The effects of nitrogen implantation conditions (ion energy, dose rate, and processing time) on the thickness and wear behavior of N-rich layers produced on 304 stainless-steel surfaces are examined. Surfaces implanted at elevated temperatures (≈400°C) with 0.4 to 2 keV nitrogen ions at high dose rates (1.5 to 3.8 mA/cm2) are compared to surfaces implanted at higher energies (30 to 60 keV) and lower current densities (0.1 to 0.25 mA/cm2). The most wear-resistant surfaces are observed when the implanted-ion energy is near 1 keV and the dose is very large (> 2 × 1019 ions/cm2). Typically, surfaces implanted under these optimum conditions exhibit load-bearing capabilities at least 1000 times that of the untreated material. Some comparisons are also made to surfaces processed using conventional plasma-nitriding. Samples treated using either process have wear-resistant surface layers in which the nitrogen is in solid solution in the fcc phase. It is argued that the deep N migration (> 1 μm) that occurs under low-energy implantation conditions is due to thermal diffusion that is enhanced by a mechanism other than radiation-induced vacancy production.

Ion Beam Synthesis By Tungsten Implantation Into 6h-Silicon Carbide At Elevated Temperatures

1996 ◽  
Vol 423 ◽  
Author(s):  
Hannes Weishart ◽  
W. Matz ◽  
W. Skorupa
Keyword(s):  
Silicon Carbide ◽  
Tungsten Carbide ◽  
Elevated Temperatures ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Bimodal Distribution ◽  
High Dose ◽  
Electrically Conductive ◽  
Implantation Temperature ◽  
High Dose Implantation

AbstractWe studied high dose implantation of tungsten into 6H-silicon carbide in order to synthesize an electrically conductive layer. Implantation was performed at 200 keV with a dose of 1×1017 W+cm−2 at temperatures of 90°C and 500°C. The samples were subsequently annealed either at 950°C or 1100°C. The influence of implantation and annealing temperatures on the reaction of W with SiC was investigated. Rutherford backscattering spectrometry (RBS), x-ray diffiraction (XRD) and Auger electron spectroscopy (AES) contributed to study the structure and composition of the implanted layer as well as the chemical state of the elements. The implantation temperature influences the depth distribution of C, Si and W as well as the damage production in SiC. The W depth profile exhibits a bimodal distribution for high temperature implantation and a customary gaussian distribution for room temperature implantation. Formation of tungsten carbide and silicide was observed in each sample already in the as-implanted state. Implantation at 90°C and annealing at 950°C lead to crystallization of W2C; tungsten silicide, however, remains amorphous. After implantation at 500°C and subsequent annealing at 11007deg;C crystalline W5Si3 forms, while tungsten carbide is amorphous.

Ion Implantation of KnbO3 and LiNbO3 at Elevated Temperatures

1988 ◽  
Vol 128 ◽  
Author(s):  
C H. Buchal ◽  
R. Irmscher ◽  
P. Günter
Keyword(s):  
Ion Implantation ◽  
Dynamic Recrystallization ◽  
Substrate Temperature ◽  
Elevated Temperatures ◽  
High Dose ◽  
Single Crystalline ◽  
First Time ◽  
High Dose Implantation

ABSTRACTIon implantation, annealing and channeling of single crystalline samples of KnbO3 and LiNbO3 have been studied. Raising the substrate temperature above 600 K, greatly increases the tolerance of the crystals for high-dose implantation. In LiNbO3 dynamic recrystallization has been observed for the first time.

scholarly journals Discoloration Effects of High-Dose γ-Irradiation and Long-Term Thermal Aging of (U)HMW-PE

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Anja Kömmling ◽  
Emmanouil Chatzigiannakis ◽  
Jörg Beckmann ◽  
Volker Wachtendorf ◽  
Kerstin von der Ehe ◽  
...  
Keyword(s):  
Thermal Aging ◽  
Elevated Temperatures ◽  
Color Change ◽  
Neutron Radiation ◽  
Radiation Shielding ◽  
High Dose ◽  
Γ Irradiation ◽  
Black Spots ◽  
Vis Spectroscopy ◽  
One Year

Two polyethylene types with ultra-high (UHMW-PE) and high molecular weight (HMW-PE) used as neutron radiation shielding materials in casks for radioactive waste were irradiated with doses up to 600 kGy using a 60Co gamma source. Subsequently, thermal aging at 125°C was applied for up to one year. Degradation effects in the materials were characterized using colorimetry, UV-Vis spectroscopy, IR spectroscopy, and DSC. Both materials exhibited a yellowing upon irradiation. The discoloration of UHMW-PE disappeared again after thermal aging. Therefore, the yellowing is assumed to originate from annealable color centers in the form of free radicals that are trapped in the crystalline regions of the polymer and recombine at elevated temperatures. For the antioxidant-containing HMW-PE, yellowing was observed after both irradiation and thermal aging. The color change was correlated mainly to decomposition products of the antioxidant in addition to trapped radicals as in UHMW-PE. Additionally, black spots appeared after thermal aging of HMW-PE.

Evolution of Defect and Impurity Profile During High Dose Co Implantation into Si at Elevated Temperatures

1993 ◽  
Vol 320 ◽  
Author(s):  
S. Schippel ◽  
A. Witzmann
Keyword(s):  
Point Defects ◽  
Elevated Temperatures ◽  
Rutherford Backscattering Spectrometry ◽  
High Dose ◽  
Impurity Profile ◽  
Gaussian Shape ◽  
Near Surface ◽  
Gaussian Distributions ◽  
Transmission Electron ◽  
Effective Center

ABSTRACT<111> -Si was implanted with 250 keV Co ions at a target temperature of 350°C. The ion dose was varied between 1 × 1014 cm−2 and 2 × 1017 cm−2. The evolution of the defect and impurity profile was investigated by Rutherford Backscattering Spectrometry (RBS), channeling and transmission electron microscopy (TEM).Up to a dose of 1 × 1015 Co cm−2 no defects can be detected. At higher Co doses, we find correlated defects in the center of the Co distribution and point defects in the region below. Moreover, damage accumulation at the surface is observed. The concentration of defects increases with increasing ion dose and reaches its level of saturation at a dose of 2 × 1016 cm−2.The Co profiles of samples implanted at 350°C differ considerably from the Gaussian shape. The near surface and the back flank are parts of Gaussian distributions. However, the standard deviation of the near surface flank is always smaller than that of the back flank. Moreover, the distributions show tails into the substrate at depths > 320 nm. This proves that radiation damage acts as an effective center for the nucleation of CoSi2.During annealing we find a redistribution of Co towards the defective regions for Co doses between 1 × 1016 cm−2 and 5 × 1016 cm−2.

scholarly journals Electrospun Semi-Alicyclic Polyimide Nanofibrous Membrane: High-Reflectance and High-Whiteness with Superior Thermal and Ultraviolet Radiation Stability for Potential Applications in High-Power UV-LEDs

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1977
Author(s):  
Xinxin Zhi ◽  
Huasen Wang ◽  
Xinying Wei ◽  
Yan Zhang ◽  
Yuancheng An ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Elevated Temperatures ◽  
Average Molecular Weight ◽  
Radiation Stability ◽  
Solid Content ◽  
High Dose ◽  
Pristine Sample ◽  
Resin Solution ◽  
Uv Leds ◽  
High Reflectance

Polymeric nanofibrous membranes (NFMs) with both high whiteness and high thermal and ultraviolet (UV) stability are highly desired as reflectors for ultraviolet light-emitting diodes (UV-LEDs) devices. In the current work, a semi-alicyclic and fluoro-containing polyimide (PI) NFM with potential application in such kinds of circumstances was successfully fabricated from the organo-soluble PI resin solution via a one-step electrospinning procedure. In order to achieve the target, a semi-alicyclic PI resin was first designed and synthesized from an alicyclic dianhydride, 3,4-dicarboxy-1,2,3,4,5,6,7,8-decahydro-1-naphthalenesuccinic dianhydride (or hydrogenated tetralin dianhydride, HTDA), and a fluoro-containing diamine, 2,2-bis[4-(4-amino-phenoxy)phenyl]hexafluoropropane (BDAF), via an imidization procedure. The derived PI (HTDA-BDAF) resin possessed a number-average molecular weight (Mn) higher than 33,000 g/mol and was highly soluble in polar aprotic solvents, such as N,N-dimethylacetamide (DMAc). The electrospinning solution was prepared by dissolving the PI resin in DMAc at a solid content of 25–35 wt%. For comparison, the conventional high-whiteness polystyrene (PS) NFM was prepared according to a similar electrospinning procedure. The thermal and UV stability of the derived PI and PS NFMs were investigated by exposure under the UV-LED (wavelength: 365 nm) irradiation. Various thermal evaluation results indicated that the developed PI (HTDA-BDAF) NFM could maintain both the high reflectance and high whiteness at elevated temperatures. For example, after thermal treatment at 200 °C for 1 h in air, the PI (HTDA-BDAF) NFM exhibited a reflectance at a wavelength of 457 nm (R457) of 89.0%, which was comparable to that of the pristine PI NMF (R457 = 90.2%). The PI (HTDA-BDAF) NFM exhibited a whiteness index (WI) of 90.88, which was also close to that of the pristine sample (WI = 91.22). However, for the PS NFM counterpart, the R457 value decreased from the pristine 88.4% to 18.1% after thermal treatment at 150 °C for 1 h, and the sample became transparent. The PI NFM maintained good optical and mechanical properties during the high dose (2670 J/cm2) of UV exposure, while the properties of the PS NFM apparently deteriorated under the same UV aging.

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