Antimony implanted silicon: A comparison between the total implanted concentration profile and the donor concentration profile

Abstract

The total concentration profiles of various doses of antimony, implanted into silicon at 100 keV, have been determined by a new technique, using Kr⁺ ions to detect selectively the antimony (as Sb-M X-rays) at the expense of the silicon. Since most of these X-rays arise from only a few tens of Angstroms below the surface of the silicon, this allows the X-ray generation to be used in conjunction with an anodic stripping technique to obtain the antimony depth distribution. These profiles are compared with others, obtained by measuring the donor concentration as a function of depth, using standard Hall effect and conductivity measurements. A significant difference between these profiles was observed, which is thought to be due to the suppression of electrical activity which occurs as the result of lattice damage. Confirmatory evidence is presented in the form of electron microscope observations of the implanted region at various depths below the silicon surface.     

Damage anneal of antimony/phosphorus double implants in silicon

A method is presented for avoiding the dislocation generation in (100) silicon implanted with phosphorus doses up to 5×10¹⁵ ions/cm² at 50 keV. The residual defects after the damage anneal are considerably reduced if the phosphorus implant is combined with a low dose, e.g. 1×10¹⁴ ions/cm², antimony implant which produces a deeper surface layer of amorphous silicon. It is essential that the phosphorus ions are implanted shallower than the antimony ions, and come to rest within the amorphous layer. Subsequent thermal annealing proceeds by a solid phase epitaxial regrowth mechanism.     

Effect of the ionization energy loss density of high-energy bismuth,krypton, and xenon ions on the development of hydrogen blisters in silicon

Radiation-induced athermal hydrogen removal from single-crystal silicon subjected to irradiation by high-energy heavy Bi⁺ (E = 710 MeV), Kr⁺ (E = 85 and 250 MeV), and Xe⁺ (130 MeV) ions is detected experimentally. The decrease in the hydrogen concentration depends on the specific ionization energy losses of high-energy heavy ions. At high specific ionization losses of Bi⁺ ions with E = 710 MeV (22.5 keV/nm), the hydrogen concentration decreases to a level at which blisters cannot be observed in an optical or electron microscope (which is likely to be 1 at % hydrogen at the peak of the calculated hydrogen concentration profile). At medium specific ionization losses of Xe⁺ ions with E = 130 MeV (12.5 keV/nm) and Kr⁺ ions with E = 250 and 85 MeV (9.5 and 8.5 keV/nm, respectively), the hydrogen concentration decreases to a level that does not affect blister formation but determines the blister failure (flaking) conditions.     

X-ray productions in symmetric heavy ion-atom collisions

X-ray measurements for 50–200 keV impact Ne⁺ → Ne, Ar⁺ → Ar and Kr⁺ → Kr show an increase of a factor of 10 in the flourescence yield for Ar-L₂₃, a similar increase may occur for Kr-M₂₃, but for Ne-K the yield does not vary much.     

Mixing of Au in Si induced by secondary and high-order recoil implantation

The mixing of Au in Si induced by secondary and high-order recoil implantation was investigated using 350 keV Ar⁺ and 350 keV Kr⁺ ions to fluences from 1?×?10¹⁶ to 3?×?10¹⁶ ions/cm² at room temperature. The thickness of the Au layer evaporated on Si substrate was ～2400 Å.The ranges of the Ar and Kr ions were chosen to be lower than the thickness of the Au layer in order to avoid the ballistic mixing produced by the primary knock-on atoms. Rutherford backscattering spectrometry (RBS) experiments were carried out to study the effects induced by Ar and Kr irradiation at the interface of Au–Si system. We observed that in the case of the irradiation with Ar⁺ ions, a broadening of the Au–Si interface occurred only at the fluence of 3?×?10¹⁶ Ar⁺/cm² and it is attributed to the surface roughening induced by ion bombardment. In contrast, the RBS analysis of a sample irradiated with 2?×?10¹⁶ Kr⁺/cm² clearly showed, in addition to the broadening effect, the formation of a mixed zone of Au and Si atoms at the interface. The mixing of Au in Si atoms can be explained by the secondary and high-order recoil implantation followed by subsequent collision cascades.     

Formation of cubic silicon carbide layers on silicon under the action of continuous and pulsed carbon ion beams

The structure and infrared absorption of cubic silicon carbide (β-SiC) layers produced by the continuous high-dose implantation of carbon ions (C⁺) into silicon (E=40 keV and D=5×10¹⁷ cm⁻²), followed by the processing of the implanted layers with a high-power nanosecond pulsed ion beam (C⁺, τ=50 ns, E=300 keV, and W=1.0–1.5 J/cm²), are investigated. Transmission electron microscopy and electron diffraction data indicate the formation of a coarse-grained polycrystalline β-SiC layer with grain sizes of up to 100 nm. A characteristic feature of such a layer is the dendritic surface morphology, which is explained by crystallization from the melt supercooled well below the melting point of β-SiC.     

Spatial distribution, build-up, and annealing of radiation defects in silicon implanted by high-energy krypton and xenon ions

An x-ray diffraction study of defect formation in silicon irradiated by Kr⁺ (210 MeV, 8×10¹²−3×10¹⁴ cm⁻²) and Xe⁺ (5.6 BeV, 5×10¹¹−5×10¹³ cm⁻²) ions is reported. It has been established that irradiation produces a defect structure in the bulk of silicon, which consists of ion tracks whose density of material is lower than that of the host. The specific features of defect formation are discussed taking into account the channeling of part of the ions along the previously formed tracks and the dominant role of electron losses suffered by the high-energy ions. It is shown that the efficiency of incorporation of stable defects by irradiation with high-energy ions is lower than that reached by implanting medium-mass ions with energies of a few hundred keV. Fiz. Tverd. Tela (St. Petersburg) 40, 1627–1630 (September 1998)     

Photoluminescence and structural defects in silicon layers implanted by iron ions

The photoluminescence spectra of silicon samples implanted by ⁵⁶Fe⁺ ions [energy, 170 keV; dose, 1×10¹⁶, (2–4)×10¹⁷ cm^?2] and annealed at temperatures of 800, 900, and 1000°C are measured. The structure of the samples at each stage of treatment is investigated using transmission electron microscopy (TEM). It is found that the phase formation and morphology of crystalline iron disilicide precipitates depend on the dose of iron ions and the annealing temperature. A comparison of the dependences of the intensity and spectral distribution of the photoluminescence on the measurement temperature, annealing temperature, and morphology of the FeSi₂ phase revealed the dislocation nature of photoluminescence.     

Investigation of the lateral spread of erbium ions implanted in silicon crystal

The erbium ions at energy of 400 keV and dose of 5×10 15 ions/cm 2 were implanted into silicon single crystals at room temperature at the angles of 0,45 and 60.The lateral spread of 400 keV erbium ions implanted in silicon sample was measured by the Rutherford backscattering technique.The results show that the measured values were in good agreement with those obtained from the prediction of TRIM’98 (Transport of Ions in Matter) and SRIM2006 (Stopping and Range of Ions in Matter) codes.     

Defects formation in the dual B+ and N+ ions implanted silicon

Silicon wafers were implanted with 40 keV B⁺ ions (to doses of 1.2×10¹⁴ or 1.2×10¹⁵ cm^–2) and 50 or 100 keV N⁺ ions (to doses from 1.2×10¹⁴ to 1.2×10¹⁵ cm^–2). After implantations, the samples were furnace annealed at temperatures from 100 to 450 °C. The depth profiles of the radiation damages before and after annealing were obtained from random and channeled RBS spectra using standard procedures. Two damaged regions with different annealing behaviour were found for the silicon implanted with boron ions. Present investigations show that surface disordered layer conserves at the annealing temperatures up to 450 °C. The influence of preliminary boron implantation on the concentration of radiation defects created in subsequent nitrogen implantation was studied. It was shown that the annealing behaviour of the dual implanted silicon layers depends on the nitrogen implantation dose.The authors would like to thank the members of the INP accelerator staff for the help during the experiments. The work of two authors (V.H. and J.K.) was partially supported by the Internal Grant Agency of Academy of Science of Czech Republic under grant No. 14805.     

Study of iron implanted MgO crystals by low-energy electron induced X-ray spectroscopy

Magnesium oxide crystals implanted with Fe⁺ ions have been studied by means of Low-Energy-Electron-Induced X-ray Spectroscopy. All the implantations were carried out with 100 or 150 keV ion energy, at doses in the range from 10¹⁵ to 10¹⁷ ions cm^?2. The structure of the Fe L_II, L_III X-ray emission bands provides information about the iron chemical state. Fe L_II/L_III band intensity ratio measurements have been performed with a 3 keV electron excitation in order to investigate the whole implanted layer. In addition, by using a filtered Fourier transform technique on observed spectra, some modifications in the oxygen K emission band can be observed in implanted MgO crystals after thermal annealings in air. The oxygen spectrum fine structure suggests that the MgO matrix, partially destroyed by iron implantation, is restored after high temperature treatments. All the implantation, is restored after high temperature treatments. All the results are discussed on the basis of previous Mössbauer Spectroscopy studies and ion channeling investigations.     

Magnetic properties of H+ implanted bubble garnet films by means of depth selective conversion electron Mössbauer spectroscopy

Bubble garnet films before and after 50 keV H⁺ implantation have been studied by means of DCEMS. The spintilt angle of the films as grown after etching off 1000 å was measured to be 30±2? relative to the surface normal at the top of the surface. The doses of implanted H⁺ ions were 2, 4 and 8×10¹⁶ ions/cm². Mössbauer spectra were measured after successive etching of the implanted layer. The magnetic hyperfine field was obtained as a function of depth. The implanted hydrogen distribution was also measured by the¹H(¹⁵N, αγ)¹²C reaction.     

Impurity redistribution in Pb implanted and annealed silicon

Reordering of 〈111〉 silicon, implanted with Pb ions at energies >100 keV and fluences ～5 × 10¹⁵ cm^?2 is accompanied by substantial impurity indiffusion in addition to pronounced outdiffusion and accumulation at the near surface region.     

Spatial distribution of defects produced by boron ion implantation of silicon

A simple technique for the study of the spatial distribution of the damage produced by ion implantation of silicon has been developed. The damage depth distribution for 40 keV boron ions in silicon has been studied at irradiation doses from 7 × 10¹¹ to 3.9 × 10¹⁴ ions/cm² and the relative defect peak depth R _d/R _p = 0.85 determined. An increase of layer conductivity as the surface part of the implanted layer is removed has been revealed. This effect is caused by the presence of radiation defects in the surface region of the layer. The “electrical” cluster diameter is about 28 A and the overlapping cluster dose is close to 1 × 10¹³ ions/cm².     

Observation of an enhanced gettering effect in silicon under germanium molecular ion implantation

Germanium atomic (Ge₁ ⁺) and molecular ions (Ge₂ ⁺) of equal energy per atom are implanted in silicon at an elevated temperature. The ion induced damage has been monitored by following the intensity variation of the LO Raman peak of Si. The germanium implanted samples have been labeled with 10 keV Au ions. The gettering of gold has been observed by Rutherford backscattering spectrometry in the post-annealed samples. This paper reports a first time observation of an enhanced gettering of gold in silicon implanted with molecular ions. PACS 61.72.Ji; 61.80.Lj; 61.80.Jh; 61.72.Yx     

低能重离子注入花生干种子深度-浓度分布的方向效应研究

用双光子激光扫描显微镜技术观测200keV V⁺离子从不同方向注入花生干种子的 深度-浓度 分布，发现沿纵向和横向注入的离子在样品中的深度-浓度分布有显著差别，即分布具有方 向效应.初步分析了造成注入离子分布出现方向效应的原因. 关键词： 离子注入 植物种子 深度-浓度分布 方向效应     

Amorphization of armco iron by boron implantation and subsequent crystallization by heat treatment: A CEMS,X-ray and ultramicrohardness study

The phase compositon of the near-surface zone of armco iron implanted with B⁺ ions (100 keV) at 200 °C was analyzed by CEMS and X-ray diffraction. The existing phases (bcc iron, Fe₂B and an amorphous Fe-B phase) were subsequently modified by heat treatment at various temperatures. The influence of the phase modifications upon the mechanical properties was studied by ultramicohardness measurements.     

The structure of a stepped copper (410) surface determined by ion scattering spectroscopy

Ion Scattering Spectroscopy applied in the multiple scattering mode is used to determine the structure of a stepped Cu(410) surface. The energy of singly scattered ions is influenced by the presence of neighbour surface atoms. This effect can be used to determine interatomic distances up to about 10Å, as is shown by the results of 8 keV Ar⁺ and 11 keV Ne⁺ scattered through θ = 50°. The edge-edge distance of the stepped copper surface appears to be in accordance with the results of LEED experiments obtained by other investigators. The experiments show a good agreement with the results of the analytical 3-atom model of Poelsema. The energy of the so-called “plateau collision” appears to depend on the effective plateau length l as measured in the plane of incidence. Lengths l between 15 and 60 Å can be determined with an accuracy of 5 Å. Results are shown for 8 and 12 keV Ar⁺, θ = 40° and 60°, and 8 keV Kr⁺ θ = 40°. The experimental dependence of the energy on lis described correctly by a phenomenological model.     

On the relative stability of different topographical features developed on bombarded copper surfaces

The morphological evolution of different topographical features (namely cones, ridges, cliffs, and featureless planes), as developed on bombarded copper surfaces as a function of consecutive doses of mass-separated 12 keV Kr⁺ ions, has been compared. The doses ranged from 1.2 × 10¹⁷ ions/cm² up to 3 × 10¹⁹ ions/cm². We found clear experimental evidence, valid at least for copper as here prepared, that the order of increasing relative stability is cone-ridge-cliff-plane.     

Study of the lateral distribution of neodymium ions implanted in silicon

Due to the need to reduce electronic device sizes,it is very important to consider the depth and lateral distribution of ions implanted into a crystalline target.This paper reports that Nd ions with energies of 200 keV to 500 keV and dose of 5×10 15 ions/cm 2 are implanted into Si single crystals at room temperature under the angles of 0,30,and 45,respectively.The lateral spreads of 200 keV-500 keV Nd ions implanted in Si sample are measured by Rutherford backscattering technique.The results show that the measured values are in good agreement with those obtained from the prediction of SRIM2010 codes.