摘要:

Boron ions in the 15–50 MeV energy range were implanted into high resistivity silicon targets. The range distributions were measured by Spreading Resistance Profilometry (SRP) and for the first time by Secondary Ion Mass Spectrometry (SIMS). The two techniques provide accurate range and straggling experimental determinations even at this large depth (∼ 100 μm). The carrier profile matches quite well the chemical profile in all the investigated samples. The profiles are characterized by a long front tail at low boron concentration due to single scattering events at large angle. The distribution around the peak is broaded by electronic straggling and in some cases by channeling effects. This latter phenomenon introduces an asymmetry around the peak. The Bethe approach in combination with large angle scattering and electronic straggling describes the profiles.

ISSN:1042-0150    

DOI:10.1080/10420159408229011

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Amorphization of GaAs by P+implantation at room temperature with fluences ranging from 2*1014to 1*1015cm−2with energies ranging from 40 to 170 keV has been investigated by means of the RBS channelling technique. The critical dose and the critical energy density for amorphization were determined. The results obtained do not confirm the expected model of homogeneous amorphization for ‘light’ P-ion implantation.

ISSN:1042-0150    

DOI:10.1080/10420159408229012

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The process of the structure restoration of GaAs implanted with Ar+ions at the ion current densities of 10 and 25 μA/cm2and in the fluence interval of 6 × 1013–1 × 1016cm−2has been analysed on the basis of Raman scattering (RS) and Rutherford backscattering (RBS) data taken into account the target heating during the irradiation. The current dependence of threshold fluences which the recrystallization begin at is explained in assumption that the structure restoration is caused of by the mobile monovacancies interaction with the stable vacancy cluster. The existence of the critical ion fluence corresponded to the most perfect GaAs structure has been shown.

ISSN:1042-0150    

DOI:10.1080/10420159408229013

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Studies of particle tracks in solids have wide ranging applications in many diverse fields of science and technology. Most of these studies require a precise knowledge of heavy ion track lengths or ranges in various knowledge of heavy ion track lengths or ranges in various commonly used solid dielectrics. We have measured the maximum etchable track lengths of132Xe at 12 different energies ranging from 5.8 MeV/u to 17.0 MeV/u in CR-39 (Homalite). The ion beam with an initial energy of 17.0 MeV/u was degraded by aluminium foils of different thickness. The detectors were irradiated at an angle of 45° to the beam direction and were etched for a period of 2–6 hrs in 6N NaOH at 55°C to reveal the tracks. The track lengths were measured using an optical microscope and the maximum etchable track lengths were determined. The standard deviations have been evaluated and the experimental results are compared with theoretical values obtained from computer codes ‘RANGE’ and ‘TRIM’ and the program of Henke and Benton.

ISSN:1042-0150    

DOI:10.1080/10420159408229014

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Metallic ions (Ti, Mo, W, V, Ni, Y, Fe and Al) extracted from a MEVVA source have been implanted up to high doses (>1 × 1017cm−2) into Al and H13 steel. Because of beam heating, rather low energy ions could penetrate quite deeper in the substrates than predicted, stable intermetallic compounds appear as fine precipitates in the doped region, and hence the retained concentration of implants even exceeds the sputter-limited maximum. Multiply charged beam, enhanced diffusion and chemical reaction give great influences to the concentration distribution of implants. All these features are strongly dependent on the chosen ion-target combination.

ISSN:1042-0150    

DOI:10.1080/10420159408229015

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Irradiation effect of the Al76Si4Mn20icosahedral quasicrystal (IQC) caused by 120 keV Ar ions and 1 MeV electrons has been studied by using transmission electron microscopy (TEM). The effect is dose and temperature dependent. At lower temperatures (≤345 K), Ar ions induces the Al-Si-Mn IQC fully amorphized. At medium temperature (352–400 K), only weak disordering and amorphization effects have been observed. At higher temperature (520∼670 K) no measurable effect has been observed by TEM. The temperature ranges are shifted to much lower temperatures for 1 MeV electron irradiation. The Ar ion and electron dual irradiation possesses the same effect as Ar ion irradiation. Heating the amorphized specimen to 600∼640 K induces it to transform to micro-quasicrystals and further heating to higher temperature (≥660 K) induces crystallization.

ISSN:1042-0150    

DOI:10.1080/10420159408229016

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The hyperfine interaction of a natural brazilian zircon sand was determined at zirconium sites between room temperature and 1393K by means of the time-differential perturbed-angular-correlations technique. Complementary measurements of x-ray diffraction, differential thermal analysis and density were also performed. It was found that the starting compound was an intermediate zircon of 4.62 g/cm3density consisting of a mixture of slightly disordered and highly defectuous materials in a ratio quite different from that determined for non brazilian zircons self irradiated by the same α-dose. Heating the sample resulted in the gradual recovery of the periodic crystalline structure in a two-stage process characterized by activation energies of 3.88 and 4.68 eV. An additional zirconium compound, for which an interpretation is proposed, was observed to be present in a low and nearly constant proportion up to 1393K, temperature at which it evidenced a reduction. A final measurement at RT revealed that this last change, as well as the second annealing stage, were of reversible nature.

ISSN:1042-0150    

DOI:10.1080/10420159408229017

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A mechanism of dislocation structure formation and its dynamics is presented. Coalescence of the interstitial atoms leads to the formation of dislocation loops. The formed loops grow due to precipitation of the interstitial atoms. Interaction between loops results in their motion deep into material, where loops form a developed dislocation structure.

ISSN:1042-0150    

DOI:10.1080/10420159408229018

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Calculations of space geometry and electron structure of self-interstitial atoms (IAs) in Si have been made in cluster approximation by using self-consistent discrete variational Xα-method (DV-Xα), semiempirical MINDO/3 method and molecular dynamic method (MD). The results of DV-Xαcalculation show that a high state density in the band gap and various spin states are observed for interstitial complexes. As follows from the analysis of the data obtained, the methods resulting from neglecting the differential overlapping, can not be used for satisfactory description of IAs properties. MD calculations prove the existence of a new stable configuration, oriented in one of the plane equivalent to (110) and containing a pair of IAs in tetrahedral cavity. The results of theoretical analysis are compared with those available in literature on the properties of IAs in Si.

ISSN:1042-0150    

DOI:10.1080/10420159408229019

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A series of gettering experiments have been carried out for a better understanding of gettering mechanism of Au atoms in silicon. Neutron activation techniques were used to study the efficiency of ion-implantation gettering of gold in gold-equilibrated silicon samples. The implantation species was 100 keV neon ions bombarded up to dose 5.1015, 1016and 5.1016ions/cm2. Next, annealing process at temperature 600°C, 800°C and 1000°C, respectively was performed. The experimental results of efficiency of gettering Gexpwere compared to the theoretical values Gthe. In this paper we propose the gettering model based on the dissociative mechanism of diffusion. We suggest, that for the temperatures up to 800°C, predominant gettering of Au atoms is governed by this mechanism.

ISSN:1042-0150    

DOI:10.1080/10420159408229020

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor