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BISOL, which was named as Beijing_ISOL before (Cui et al., 2013), is the abbreviation of Beijing Isotope-Separation-On-Line neutron beam facility. It is proposed jointly by Peking University (PKU) and China Institute of Atomic Energy (CIAE) for basic science study and application. It is a double driven facility that can be driven by a reactor or a deuteron accelerator. The deuteron driver accelerator should accelerate the deuteron beam up to 40 MeV with maximum beam current of 10 mA. Proton beams up to 33 MeV and He2+ beams up to 81.2 MeV can also be accelerated in this accelerator. The accelerator can be operated on either CW (continuous waveform) or pulsed mode, and the ion energy can be adjusted in a wide range. The accelerator will also allow independent operation of the RIB (Radioactive Ion Beams) system. It will be mainly charged by PKU group. Details of the deuteron accelerator preliminary design for BISOL will be given in this paper.

Some unique characteristics of epitaxial growth of oxide thin films prepared by pulsed laser deposition have been observed in this study. The study demonstrates that deposition temperature is one of the most important parameters in controlling orientation and epitaxial growth of oxide thin films. Higher temperature is usually imperative for the epitaxial growth. The threshold temperature for epitaxial growth of oxide film depends on the substrate materials, which relate mainly to the lattice mismatch and component similarity between the film and the substrate. A small lattice mismatch and a high component similarity are favorable to epitaxial growth and may decrease the epitaxial threshold temperature significantly. In addition, the orientation of CeO 2 film, grown on Si substrate, possess a unique dependence on ambient oxygen pressure, which demonstrates the significant influence of oxygen pressure to the epitaxial orientation of oxide thin films.

Epitaxial CoSi2 layers were grown on Si(1 0 0) using molecular beam allotaxy. Boron ion implantations and rapid thermal oxidation (RTO) were performed. During oxidation, SiO2 formed on the surface of the CoSi2 layers, and the silicides was pushed into the substrate. The diffusion of boron was slightly retarded during oxidation for the specimen with a 20 nm epitaxial CoSi2 capping layer as compared to the specimen without CoSi2 capping layer. The electrical measurements showed that the silicide has good Schottky contacts with the boron doped silicon layer after RTO. A nanometer silicide patterning process, based on local oxidation of silicide (LOCOSI) layer, was also investigated. It shows two back-to-back Schottky diodes between the two separated parts of the silicide.

Epitaxial growth of La 0.5 Sr 0.5 CoO 3 (LSCO) film has been achieved by pulsed laser deposition. Widely used substrates, MgO, SrTiO 3 and LaAlO 3 were chosen to examine the effect of the substrates on the growth of LSCO films. The influence of the substrate temperatures ( T s ) on the characteristics of the LSCO films was studied in a temperature range of 500–850°C. The LSCO films deposited at substrate temperatures of T s =800–850°C show good epitaxial features, better than that of the films deposited at lower T s . The experimental results reveal that the lattice mismatch and the difference of the expansion coefficients between the substrates and the LSCO films are important in the growth process of the LSCO films.

CeO2 thin films were grown on (1 0 0) silicon substrates by pulsed laser deposition. X-ray diffraction results indicated that fully (1 1 1) oriented and highly (1 0 0) oriented CeO2 films on Si (1 0 0) were achieved, respectively. Oxygen pressure was found to be important to control the crystallographic orientation. A possible mechanism was proposed to explain these results. Auger electron spectroscopy and Rutherford backscattering spectrometry analysis showed an uniform concentration distribution of Ce and O throughout the epitaxial layer independent of the oxygen pressure. The electrical properties of the films were characterized by capacitance–voltage measurements.

MeV Au + ions were implanted into LiNbO 3 with different fluences ranging from 4 × 10 13 to 5 × 10 14 ions cm −2 at room temperature. In order to investigate the influence of angle of incidence and cut direction of crystal on the damage profile, MeV Au + irradiation in LiNbO 3 was performed under different angles: 7°, 45° and 60° with different cut directions: y -cut and z -cut. The damage behaviour was studied by the Rutherford backscattering (RBS)/channelling technique. A dechannelling analysis of multiple scattering has been made. The extracted damage profile is compared with the TRIM (Transport of Ions in Matter) prediction. The effect of the fluence, ion irradiation angle and crystal cut direction on the damage profile is discussed.

Growth of (K 0.5 Na 0.5 ) 0.2 (Sr 0.75 Ba 0.25 ) 0.9 Nb 2 O 6 (KNSBN) films on (0 0 1) MgO substrates and on (0 0 1) oriented La 0.5 Sr 0.5 CoO 3 (LSCO) layers by pulsed laser deposition has been studied. X-ray diffraction θ–2θ scans indicated that the KNSBN films were of c -axis orientation. X-ray Phi scans on the (2 2 1) reflection revealed that the films grown on the MgO substrates were epitaxial growth with two [1 0 0]KNSBN in-plane orientation rotating about ±18° with respect to [1 0 0]MgO. Sandwich structures of KNSBN films with LSCO as top and bottom electrodes have been performed on (0 0 1)LaAlO 3 (LAO) substrates. The measurements of the ferroelectricity of the as-grown film gave hysterisis loop with the remnant polarization of P r ∼ 8 μ C cm −2 and the coercive field of E c ∼ 55 KV cm −1 .

Semicontinuous niobium and silver films were made in an ultra-high-vacuum (UHV) chamber and in-situ d.c. resistance measurements were performed. After interrupting the deposition, we investigated the immediate ageing phenomenon (relaxation) of the sample resistance on a time scale of about 10 min. Resistance increase and decrease were observed for niobium and silver samples, respectively. The intensity of the relaxation is sensitive to substrate temperature and film thickness. We suggest that edge diffusion and coalescence of islands due to thermomigration of the metal atoms are responsible for the resistance relaxation.

In situ DC resistance measurements were performed on semicontinuous niobium and silver films, which were made on mica and fullerene substrates in an ultra-high-vacuum(UHV) chamber. Right after the interruption of the deposition, we investigated the changes(relaxation) of the sample resistance on a time scale of about 10 minutes. Resistance increase was observed for Nb/mica and Ag C 60 systems, and decrease for Ag/mica system. The relaxation is sensitive to substrate temperature and film thickness. We suggest that the edge diffusion and mergence of islands due to thermomigration of the metal atoms are responsible for the resistance relaxation. The intensity and direction of the relaxation reflect the interfacial activity of the metal/substrate system. The heterogeneities on substrate may also play an important role during this process.

In this paper, the recent progress and applications of ion beam defect engineering (IBDE) are reported. IBDE in silicon shows that it can be used for (1) the reduction of secondary defects created by the dopant-ion implantation, (2) the gettering of F atoms from the B doped regions in BF2 implanted silicon; (3) the reduction of B diffusion in BF2 implanted silicon. IBDE applications in optoelectric crystals are also investigated. Waveguide can be formed in LiNbO3 by MeV Cu ion implantation and in KTiOPO4 (KTP) by multi-energy (MeV) He ion implantation. Mechanisms and trends of IBDE in the future are also discussed.

New empirical equations describing the rate of ion-induced crystallization at a Si crystal/amorphous interface have been developed. In our model, crystallization/amorphization at the interface arises from formation of hot spots and of knock-ons in the collision cascades. It is presumed that the hot spots induce amorphous-to-crystal transformation which lowers the free energy, similarly to heating to high temperatures, and that the bond rearrangement by a series of displacements by knock-ons and recombination to the original lattice point in collision cascades can lead to both crystal-to-amorphous and amorphous-to-crystal transformations. In both hot-spot and knock-on effects, the presence of di-vacancies under irradiation with ion beams is assumed to prohibit crystallization. The model can explain the experimental observation that the crystallization/amorphization rate is scaled by X = o 1 2 exp (C v /2kT) , the product of the root of the flux and the inverse of root of the Boltzmann factor for the motion of the di-vacancies. Crystallization rate in the hot-spots derived assuming that an incident ion induces spontaneous crystallization within a characteristic volume along the track reveals that the radius is 10 atomic distances and the thickness of is about 0.3 monolayer for 1.5 MeV Xe ions. The calculated crystallization/amorphization rate fits to experimental results over a wide temperature range.

The scattering peak of the elastic resonance of 3.045 MeV 4He with 16O shows a broadened half-width in Rutherford backscattering/channelling measurement for LiNbO3, LiTaO3, KTiOPO4 (KTP) and Sr.61Ba.39Nb2O6 (SBN) crystals. The effect was explained as due to the difference of stopping power between the channelling and nonchannelling 4He ions. The ratio of the channelled stopping power to the random stopping power of 4He2+ was deduced from the different half-width (FWHM) of channelled and random stopping power. The determined stopping power ratios are 78.6, 77.8, 75.7 and 73.0% for virgin LiNbO3, LiTaO3, KTP and SBN crystals, respectively.

High energy (MeV) Cu ions were implanted into n‐type Si samples at angles of 7°, 30°, 45°, and 60°. The doses were 5×1014 and 2×1014 ions/cm2. The damage profiles in Si(100) were investigated by a Rutherford backscattering/channeling technique with 2.1 MeV He ions. The longitudinal damage straggling and lateral damage spread are estimated for 1.0 MeV Cu+ implanted in Si(100). The values obtained are compared with the trim (transport of ions in matter) code. The results show that the longitudinal damage straggling is found to be in good agreement with the calculated one within 13% by use of the trim code, but the experimental value of the lateral damage spread is higher than the calculated one by about 28% using the trim code. The effect of dose rate, energy, and dose on damage distribution is investigated also.

Potassium titanyl phosphate (${\mathrm{KTiOPO}}_{4}$ or KTP) is a quadriatomic material made of O, P, K, and Ti which crystallizes in an orthorhombic structure with space group Pna2. The virgin KTP at different axial orientation, 〈100〉, 〈001〉, and 〈010〉, has been investigated by the channeling technique. The obtained corresponding minimum yields are 3.8, 4, and 11 %, respectively. Damage in KTP was created by 200 and 400 keV He-, Xe-, and Hg-ion irradiations with the dose varying from 1\ifmmode\times\else\texttimes\fi{}${10}^{13}$ to 1\ifmmode\times\else\texttimes\fi{}${10}^{16}$ ions/${\mathrm{cm}}^{2}$. The effect of ion mass, energy, dose, annealing temperature, and orientation of KTP on the damage has been studied. The number of displaced atoms, the damage peak, and damage width are extracted from the experimental data. The numbers of the displaced atoms obtained are compared with the trim code (the transport of ions in the matters). The result shows that the experimental numbers of the displaced atoms are in agreement with theoretical ones predicted by the trim code within the order of the magnitude. Also for the case of He ion implanted in KTP to a dose of 1\ifmmode\times\else\texttimes\fi{}${10}^{16}$ ions/${\mathrm{cm}}^{2}$, the recovery of the crystallinity of the KTP is observed after 800 \ifmmode^\circ\else\textdegree\fi{}C annealing.

Xe ions at energies from 50 to 350 keV, at increments of 50 keV, were implanted into Si3N4 films. The mean projected range and range straggling are measured by Rutherford backscattering using 2.1 MeV He ions. The longitudinal distribution parameters obtained are compared with our calculation procedure based on Biersack's angular diffusion model and Monte Carlo simulation (TRIM'89 code). Also the lateral spread of 100 keV Xe ions in Si3N4 film is obtained by means of implantation at tilted angles and Rutherford backscattering. The measured lateral spread is compared with TRIM'89. The result shows that the lateral spread of 100 keV Xe ions implanted in Si3N4 film is in good agreement with the TRIM'89 prediction within experimental error.

Ferroelectric PbTiO3 films were deposited by ion‐beam‐assisted deposition (O2+Ar 75–150 eV). The effects of ion bombardment on the Pb/Ti ratio and the structures of the film are discussed. For a given target‐substrate distance and substrate temperature, the Pb/Ti ratio decreased with increasing bombarding beam energy. Compared with the films deposited without ion bombardment, the deposition rate was increased under ion bombardment, which is attributed to an increase in the surface reaction rate. The crystal grains are larger for films deposited under ion bombardment, which implies that ion bombardment enhances the surface mobility of adatoms and hence the growth kinetics of the growing films. Dielectric and ferroelectric properties of the as‐deposited films are also reported.

X, Y, and Z crystalline cut LiNbO3 crystals were implanted by 1.0 MeV F ions with a dose of 1×1015 ions/cm.2 The virgin and implanted LiNbO3 crystals were investigated using the Rutherford backscattering/channeling technique. The obtained minimum yields of virgin crystals were 4%, 8%, and 6% for X‐, Y‐, and Z‐cut LiNbO3 crystals, respectively, because of their different arrangements of lattice sites in channeling direction. The measured damage profiles are also influenced by the arrangement of lattice sites in channeling measurements. The damage profiles of X‐cut LiNbO3 crystal induced by 1.0 MeV F+ at a fluence range of 1×1014–3×1015 ions/cm2 have been studied and compared with the Transport of Ions in Matter, version 1990 calculation. It has been found that not only the nuclear energy deposition but also the electronic energy deposition influences the defect production.

The susceptibility profile of thin ferroelectric films was calculated in this paper from Landau phenomenological theory. The dependence of mean susceptibility on the film thickness L was discussed. Depending on the parameter δ, the so-called “extrapolation length” which measures the strength of the coupling in the surface layer, two different results are obtained. For δ>0, a size driven phase transition was suggested. Near the critical thickness L o, the mean dielectric susceptibility can be expressed as Xf ' Xb[1 + Co/(L - Lo)]. For δ>0, the mean susceptibility decreases logarithmically with the decrease in film thickness.

80–100 keV Ar+, 200 keV Xe+, and 200 keV Hg+ were implanted into Si3N4 films under angles of 0°, 45°, 60°, and 75°. Both normal and oblique incidence Rutherford backscattering of 2.1 MeV He ions have been used to study tilted angle implantation, i.e., the lateral spread of Ar, Xe, and Hg ions in the Si3N4 films. The results extracted are compared with the simulation of transport of ions in matter (TRIM’89 code). The experimental lateral spread seems to be in good agreement with the TRIM’89 prediction.

The effects of 1 MeV Cu ion implantation in LiNbO3 crystals have been investigated using the Rutherford backscattering/channeling technique. The samples have been implanted with doses ranging from 5×1014 ions/cm2 to 2×1015 ions/cm2. The damage profiles have been deconvoluted from Rutherford backscattering spectra after considering the energy spreading due to difference of stopping power between nonchanneled and channeled particles. The energy dependence of the scattering cross section and stopping power have also been taken into account. The damage profiles have compared with TRIM’89 (Transport of Ions in Matter, version 1989) code calculation. For the lowest dose (5×1014 ions/cm2) implantation, the damage profile is in agreement with the defect profile calculated using the trim code. The damage peak is located shallower than the theoretical ion mean projected range, but the damage spread is larger than the ion spread. For higher dose implantations, a broadening of the damage profiles is observed, probabl...

Structure changes of PbTiO 3 films induced by ion implantation with Ar + and N + were measured by X-ray diffraction and MeV 4 He + Rutherford backscattering. The lead segregation which occurred in the volume of the collision cascade and the amorphization of the surface layer of the films are discussed.

A new concept of ion beam defect engineering is proposed. Reduction of secondary defects in 1 MeV As ion‐implanted Si(100) has been investigated by Rutherford backscattering/channeling and high resolution electron microscopy. It is found that the additional irradiation of 1.6 MeV Si ions prior to two‐step thermal annealing leads to a noticeable reduction of secondary defects. Good recrystallization of a buried amorphous layer is also obtained by irradiation of 1.6 MeV, 2×1015 Si/cm2 into the implanted Si sample held at elevated temperatures.

The surface of PbTiO3 films prepared by the sol‐gel method was analyzed by the use of x‐ray photoelectron spectra combined with secondary‐ion mass spectra and infrared absorption spectra. The results suggested that traces of organic materials still existed at least in the surface layer of the films. The outmost surface was partly covered by adsorbed oxygen. The surface layer of the film deviated from stoichiometry because of the shortage of Ti; the thickness of it was estimated about 400 A.

Transparent and crack-free Bi 2 Ti 2 O 7 thin films with strong (111) orientation were successfully prepared on n-Si(100) by chemical solution deposition (CSD) using bismuth nitrate and titanium butoxide as starting materials. The structural properties were studied by X-ray diffraction. The dielectric constant at 100 kHz at room temperature was 118 and loss factor was 0.074, for a 0.4-μm-thick film annealed at 500°C for 30 min. The leakage current density was 4.06×10 −7 A/cm 2 at an applied voltage of 15 V.

A detailed survey of the currently available data for the energy loss straggling of hydrogen, helium and heavy ions in matter has been undertaken. An empirical formula based on Chu's calculation has been obtained for the energy loss straggling of hydrogen ions. Using this formula with the effective charge and the scaling of straggling, similar to the scaling of stopping powers, good estimates have been made for He and heavy ions. The empirical formulae represent the available data accurately and permit reliable estimates for combinations of projectile and target where currently no data is available.

Potassium titanyl phosphate (KTiOPO4 or KTP crystal) is a quadriatomic target made of O, P, K and Ti. Xe ions were implanted in amorphous potassium titanyl phosphate at energies from 50 to 400 keV. The range profiles of Xe ions implanted in KTP were analyzed by Rutherford backscattering of 2.1 MeV He ions. The mean projected ranges and range stragglings are compared with our calculated value based on Biersack's angular diffusion model and Monte Carlo simulation. The results show that the obtained mean projected range is in good agreement with our calculated value, the range straggling is higher than the calculated value. But significant deviation from the transport of ions in matter (TRIM'89) prediction is found.

Mercury ions were implanted in amorphized potassium titanyl phosphate (KTiOPO4) in the range of 50–400 keV. The implanted depth distribution was measured by Rutherford backscattering of 2.1 MeV He ions. The mean projected ranges and range stragglings obtained are compared with our calculation based on Biersack’s angular diffusion model and Monte Carlo simulation. The results show that the experimental mean projected range is in good agreement with the calculated value within the experimental errors but the range straggling is systematically higher than the calculated value. However, significant deviations from the transport of ions in matter (TRIM’89) prediction for mean projected range and range straggling are found.

A new model for ion‐induced crystallization and amorphization at the interface is presented. The model is based on the general concept for ion‐induced processes between two solid phases with different free energies; the presence of pure ballistic and thermally enhanced processes. The parameters that can fit quantitatively to the temperature, flux, and stopping power dependencies of crystallization/amorphization rates for Si are obtained.

Reduction of secondary defects in 50 keV, 2×1015 BF2/cm2 implanted Si(100) has been studied by Rutherford backscattering and channeling technique. Secondary defects with high densities have been found in BF2 implanted Si(100) after thermal annealing and rapid thermal annealing. However, a noticeable reduction of secondary defects in BF2 damaged region was observed when a buried amorphous layer was formed by an additional irradiation of 1.0 MeV Si+ ions prior to annealing (i.e., ion beam defect engineering process).

The effects of ion beam defect engineering (IBDE) in BF/sub 2/-implanted silicon have been studied. It has been shown that IBDE technique may be useful in the improvement of the properties of BF/sub 2/ implanted silicon. Reduction of secondary defects in BF/sub 2/ doped region and the anomalous diffusion of B atoms was observed if a buried amorphous layer was introduced by MeV Si ion irradiation prior to annealing.

Shallower carrier concentration profiles in 50 keV P+‐implanted Si(100) after annealing at 1000 °C for 1 h have been observed when a buried amorphous layer was formed by an additional irradiation of 1.0 MeV Si+ ions prior to annealing (i.e., ion beam defect engineering process). The secondary defects formed in the MeV Si+ damaged region act as gettering sites for the collection of interstitials from the shallower depths which are responsible for the transient diffusion of P, and therefore the transient diffusion of P is reduced and the carrier concentration profiles become shallower.

150 keV Xe ions were implanted in potassium titanyl phosphate (KTP) at different angles of 0°, 45°, 60°, and 75°. The lateral straggling of Xe ions in KTP was investigated by normal and oblique incidence Rutherford backscattering of 2.1 MeV He ions. The result extracted is compared with the Monte Carlo code TRIM’89. The lateral straggling is seemed to be in a good agreement with TRIM’89 simulation within experimental error.

200 keV Hg ions were implanted in Si3N4 at different angles of 0°, 45°, and 75°. The lateral straggling of Hg ions in Si3N4 was studied by glancing angle and normal Rutherford backscattering of 2.1 MeV He ions. The obtained result is compared with the Monte Carlo code trim ’89. The lateral straggling is found to be in good agreement with the prediction.

The y-cut LiNbO3 was implanted by 3.0 MeV He+ to a dose of 2×1016 ions/cm2 at liquid nitrogen temperature. The eight black and bright modes from He implanted LiNbO3 waveguide were observed before and after rapid annealing. The refractive index profile is obtained by means of a non-stationary mode index calculation. The comparison of refractive index profile with damage profile is given. The result shows that the peak position of the refractive index profile is found to be in good agreement with the peak position of damage profile induced by 3.0 MeV He+ implanted in LiNbO3 based on transport of ions in matter (TRIM'92).

300 keV Kr 4+ ion-bombardment at a dose of 5 × 10 15 cm −2 has been applied to initiate mixing of 250 A W and Au coatings on Cu single crystals. CuAuCu and CuWCu sandwiches have also been studied, using 2 MeV 2 4 He + Rutherford backscattering as an analytical tool. In contrast to the CuAu system, no CuW alloys are known to exist under normal thermodynamic conditions which allow the formation of metastable CuW alloys by ion beam mixing. In addition, from the point of view of recoil implantation and cascade mixing the CuAu and CuW systems are quite similar, so the comparison may provide a test of the current theories for ion beam mixing. Room temperature irradiations show that CuAu mix readily, whereas hardly any mixing is observed for the CuW system. This clearly shows that any realistic model of ion beam mixing must include the thermodynamic properties of the species involved.

MeV ion implantation in Si above a dose of 1014/cm2 leads to secondary defect formation in a buried layer, which is rather stable. Annealing of Si(100) implanted with 2.0 MeV B+ ions to a dose of 2.2×1014/cm2 has been investigated by means of cross‐sectional transmission electron microscopy. After annealing at 900 °C for 15 min, dislocation loops elongated along [110] were found. A remarkable decrease in secondary defect formation has been observed if, in addition, 140 keV Si+ was implanted prior to annealing.

The effects of post-ion implantation on the properties of P + N junction formed by BF 2 ion implantation in SiO 2 /Si (1 0 0) have been studied in this paper. As for the post-irradiation using MeV Si ions, there is a critical dose for Si ions. When the dose is less than the critical dose, post MeV Si ion irradiation induces reduction of the anomalous diffusion of B atoms. However, when the dose is higher than the critical dose, MeV Si ion irradiation induces further enhancement of the anomalous diffusion of B atoms. As for the electrical properties of the P + N junction, post-ion irradiation using 1.0 MeV 5 × 10 14 Si/cm 2 reduced the density of the leakage currents by three orders of magnitude. The post-Si ion irradiation either by MeV ions or 70 keV ions leads to a reduction of the breakdown voltage of the junction.