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The effect of excimer laser pretreatment on diffusion and activation of boron implanted in silicon.

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We have investigated the effect of excimer laser annealing ELA on transient enhanced diffusion TED and activation of boron implanted in Si during subsequent rapid thermal annealing RTA. This is attributed to several mechanisms abbt as liquid-state annealing of a fraction of the implantation induced defects, introduction of excess vacancies during ELA, and solid-state annealing of the defects beyond the maximum melting depth by the heat wave propagating into the Si wafer.

Implantation of boron in silicon. The distribution versus depth of boron implanted in silicon and the corresponding electrical activity abnr after annealing are studied. The boron distributions are measured by secondary-ion mass spectrometry. Boron distributions implanted at energies in the range from 30 keV to keV in amorphous and polycrystalline silicon are analysed.

Moments of these distributions are determined by a curve-fitting programme and compared with moments calculated by Winterbon. Boron distributions obtained by implantations along a dense crystallographic direction in monocrystalline silicon are found to have penetrating tails.

After investigation of some possible mechanisms of tail formation it is concluded that the tails are due to channelling.

It was found that the behaviour of boron during annealing is determined by the properties of three boron fractions consisting of precipitated boroninterstitial boron and substitutional boron. The electrical activity of the boron versus depth agnt found to be consistent with the three boron ant. A peculiar redistribution of abt is found which is induced by the implantation of a high dose of heavy ions and subsequent annealing.

1520 mechanisms which may cause the observed effects, such as thermal diffusion which is influenced by lattice strain and damage, are discussed.

Dopant redistribution and electrical activation in silicon following ultra-low energy boron implantation and excimer laser annealing. High-resolution transmission electron microscopy has been used to assess the as- implanted damage and the crystal recovery following ELA.

The electrical activation and redistribution of B in Si during ELA has been investigated 1520 a function of the laser energy density melted depththe implant dose, and the number of laser pulses melt time. The activated and retained dose has been evaluated with spreading resistance profiling and secondary ion mass spectrometry.

A significant amount of the implanted dopant was lost from the sample during ELA. However, the dopant that was retained in crystal material was fully activated following rapid resolidification. The nbrr activation was increased for high laser energy density annealing when avnt dopant was redistributed over a deeper range. Ion implantation of abt in germanium.

All three traps anneal out at low temperatures 0 C. Depth resolved investigations of boron implanted silicon. We have 1520 the depth distribution and structure of defects in boron implanted silicon 0 0 1. Cross-section transmission electron microscopy was used to gain complementary information. In addition we have determined the strain distribution caused by the boron implantation as a function of depth from rocking curve measurements.

Tribological properties of nitrogen implanted and boron implanted steels. Samples of a steel with high chrome content was implanted separately with 75 keV nitrogen ions and with 75 keV abht ions. Retained doses were measured using resonant non-Rutherford Backscattering Spectrometry. Tribological properties aabnt determined using a pin-on-disk test with a 6-mm diameter ruby pin with a velocity of 0. Wear rate and coefficient of friction were determined from these tests.


While reduction in the wear rate for nitrogen implanted materials was observed, greater reduction more than an order of magnitude was observed for boron implanted materials.

In addition, reduction in the coefficient of friction for high-dose boron implanted materials was observed. Nano-indentation revealed a hardened layer near the surface of the material.

Results from grazing incidence x-ray diffraction suggest the formation of Fe 2 N and Fe 3 N in the nitrogen implanted materials and Fe 3 B in the boron implanted materials. Results from xbnt electron microscopy will be presented. Boron -enhanced diffusion of boron from ultralow-energy boron implantation. The authors have investigated the diffusion enhancement mechanism of BED boron enhanced diffusionwherein the boron diffusivity is enhanced three to four times over the equilibrium diffusivity at 1, C in the proximity of a silicon layer containing a high boron concentration.

It is shown that BED is associated with the formation of a fine-grain polycrystalline silicon boride phase within an initially amorphous Si layer having a high B concentration. Formation of the shallowest possible junctions by 0. Helium behaviour in implanted boron carbide. Directory of Open Access Journals Sweden.

Full Text Available When boron carbide is used as nvr neutron absorber in nuclear power plants, large quantities of helium are produced. To simulate the gas behaviour, helium implantations were carried out in boron carbide. The determination of the helium abnh coefficient was carried out using the 3He d,p4He nuclear reaction NRA method. The dynamic of helium clusters was observed by transmission electron microscopy TEM of samples implanted with 1.

Microhardness of borontitanium, and nitrogen implanted steel. Abnh implantation energy varied from to keV. Implanted samples are heat-treated at to 0 Zbnt in vacuum. The microhardness of implanted samples is measured by using a Hanneman tester with loads ranging from 2 to 40 g. The influence of annealing temperature on microhardness of the implanted layers is determined.

The diffusion of boron from the implanted layers is also investigated by using the secondary ion mass spectrometer.

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The diffusion coefficients of boron in steel are determined. Defects in 159220 ion implanted silicon. Contrast analysis and annealing kinetics show at least two different kinds of linear rod-like defects along broken bracket broken bracket directions.

One kind either shrinks nbe remaining on broken bracket broken bracket at high temperatures greater than 0 Cor transforms into a perfect dislocation loop which rotates toward broken bracket broken bracket perpendicular to its Burgers vector. The other kind shrinks steadily at moderate temperatures approximately 0 C. The activation energy for shrinkage of the latter 3. The depth distribution of all these defects was determined by stereomicroscopy.

Si samples containing B and samples containing no B P-doped were irradiated in the kV electron microscope. Irradiation at 0 C resulted in the growth of very long linear defects in the B-doped samples but not in the others, suggesting that at 0 C Si interstitials produced by the electron beam replace substitutional B some of which precipitates in the form of long rods along broken bracket broken bracket.

Modeling of interstitial diffusion of ion- implanted boron. A model of the interstitial diffusion of ion- implanted boron during rapid thermal annealing of silicon layers previously amorphized by implantation of germanium has been proposed.

It is supposed that the boron interstitials are created continuously during annealing due to generation, dissolution, or rearrangement of the clusters of impurity atoms which are formed in the ion- implanted layers with impurity concentration above the solubility limit.

The local elastic stresses arising due to the difference of boron atomic radius and atomic radius of silicon also contribute to the generation of boron interstitials. A simulation of boron redistribution during thermal annealing for 60 s at a temperature of C has been carried out.


The calculated profile agrees well with the experimental data. A number of the parameters of interstitial diffusion have been derived. In particular, the average migration length of nonequilibrium boron interstitials is equal to 12 nm. It was also obtained that approximately 1. Depth profiling of boron implanted silicon by positron beam. Positron depth profiling analyses of low energy implants of silicon aim to observe tbe structure and density of the vacancies generating by implantation and the effect of annealing.

This work present the results to several set of data starting S and W parameters. Boron -enhanced diffusion in excimer laser annealed Si. RTA 30 s at deg. C of the as- implanted and ELA-treated samples leads to a diffusion of B with diffusivities exceeding the equilibrium one and the enhancement is similar for both of the samples. The similarity of the B diffusivity for the as- implanted and ELA-treated samples suggests that the enhancement of the B diffusivity is due to the so-called boron -enhanced diffusion BED.

Possible mechanisms of BED are discussed. Comparison of boron and neon damage effects in boron ion- implanted resistors. Boron and neon damage implants were used in fabricating integrated-circuit resistors in silicon. Resistor properties were studied as functions of damaging ion species and dose.

Sliding behavior of boron ion- implanted stainless steel. The authors have studied the influence of boron ion implantation on the friction and wear behavior of stainless steel.

The authors find an increase in microhardness following implantation. The authors also observed a reduction in wear and coefficient of friction. They have measured the microhardness, inside the wear tracks and have found a large increase in the values in the unimplanted specimens and only a small increase in the implanted specimens.

These observations have thrown light on the change in the wear mechanism between the two cases. The authors have also used Scanning Electron Microscopy and Energy Dispersive Analysis of X-rays, to characterize the differences in the mode of wear.

The change in wear behavior is brought about by the ability of boron to prevent the surface from transforming into a hard brittle layer during wear.

Laser -induced photochemical enrichment of boron isotopes. A boron trichloride starting material containing both boron isotopes and boron isotopes is selectively enriched in one or the other of these isotopes by a laser -induced photochemical method involving the reaction of laser -excited boron trichloride with either H 2 S or D 2 S.

The method is carried out by subjecting a low pressure gaseous mixture of boron trichloride starting material and the sulfide to infrared radiation from a carbon dioxide TE laser.

The wave length of the radiation is selected so as to selectively excite one or the other of boron BCl 3 molecules or boron BCl 3 molecules, thereby making them preferentially more reactive with the sulfide. The laser -induced reaction produces both a boron -containing solid phase reaction product and a gaseous phase containing mostly unreacted BCl 3 and small amounts of sulfhydroboranes.

Pure boron trichloride selectively enriched in one of the isotopes mbr recovered as the primary product of the method from the gaseous phase by a multi-step recovery procedure. Pure boron trichloride enriched in the other isotope is recovered as a secondary product abjt the method by the subsequent chlorination of the solid phase reaction product followed by separation of BCl 3 from the mixture of gaseous products ant from the chlorination.

Separation of boron isotopes by infrared laser. Vibrationally excited chemical reaction of boron tribromide BBr 3 with oxygen O 2 is utilized to separate 10 B and 11 B.