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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.

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.

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.

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.

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.

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.

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.