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We have explained the role of fluorine in the reduction of the self-interstitial population in a preamorphized Si layer under thermal treatment. For this purpose, we have employed a B spike layer grown by molecular-beam epitaxy as a marker for the self-interstitial local concentration. The amorphized samples were implanted with 7x10(12), 7x10(13), or 4x10(14) F/cm(2) at 100 keV, and afterwards recrystallized by solid phase epitaxy. Thermal anneals at 750 or 850 degreesC were performed in order to induce the release of self-interstitials from the end-of-range (EOR) defects and thus provoke the transient enhanced diffusion of B atoms. We have shown that the incorporation of F reduces the B enhanced diffusion in a controlled way, up to its complete suppression. It is seen that no direct interaction between B and F occurs, whereas the suppression of B enhanced diffusion is related to the F ability in reducing the excess of silicon self-interstitials emitted by the EOR source. These results are reported and discussed

We present measurements of the stopping power of 800-keV 4 He ions channeled along the Si͗100͘ axis, as a function of the incidence angle. We compare the experimental results with theoretical calculations by using the impact-parameter-dependent energy loss obtained from the solution of the time-dependent Schrödinger equation through the coupled-channel method. This nonperturbative calculation provides reliable energy-loss results which are in good agreement with the experimental results. ͓S0163-1829͑97͒08607-4͔

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The lattice location of F atoms in Si was experimentally studied. Si single crystals were amorphized, implanted with F, and afterwards the amorphous layer was recrystallized. Some of the samples prepared in this way were also annealed at 750°C for 60 min. The 19 F͑p , ␣␥͒ 16O resonant nuclear reaction at 340.5 keV was employed to measure the probability of a close encounter between protons and F nuclei as a function of the incident angle with respect to six major crystalline directions. The predictions of several ab initio calculations proved to be incompatible with the present experimental findings. The miniaturization of complementary metal-oxidesemiconductor ͑CMOS͒ devices requires the confinement of dopants very close to the surface. In the microelectronics industry, the dopants are introduced through ion implantation. This technique is widely used because the depth and concentration of the dopant are easily controlled and reproduced. However, the implantation process generates point defects ͑self-interstitials and vacancies͒ in the target at a concentration well above the thermodynamical equilibrium level.1 These defects undesirably accelerate the dopant diffusion. This phenomenon is called transient-enhanced diffusion ͑TED͒, and it may be several orders of magnitude faster than normal thermal diffusion. TED is particularly dramatic for boron, 2 the most frequently used p dopant, hindering thus the further miniaturization of CMOS devices.In order to reduce the boron TED, coimplantation of F is currently used in the microelectronics industry, although the role F plays in the reduction of boron TED has not yet been entirely understood. To better understand the mechanism whereby F leads to a decrease of boron TED, substantial experimental and theoretical work has been carried out. Up to now, it is known that the slowing down of boron TED occurs by the interaction between F and point defects, and it has been suggested that F atoms form complexes with these defects. [3][4][5][6][7][8][9] By ab initio calculations, several authors 5,7,8,10 have found that the lowest-energy state for a single interstitial F in Si is at the bond-centered the ͑BC͒ site in the +1 charge state or at the tetrahedral ͑T͒ site in the −1 charge state, depending on the Fermi energy. However, in Refs. 5 and 7 it was obtained that fluorine-vacancy ͑FV͒ complexes are highly favored over the interstitial configuration. From the experimental standpoint, the detection of FV complexes by positron annihilation spectroscopy has been reported in Refs. 3, 4, and 9 and also through sheet resistance measurement in Ref. 6. On the other hand, electric quadrupole hyperfine interaction and preliminary channeling experiments have indicated that F might occupy either bond or antibonding ͑AB͒ interstitial sites. 11,12 In the present work, the lattice location of F atoms in Si was experimentally investigated. Czochralski n-type ͑P-doped͒ ͗100͘-Si single crystals with 10-20 ⍀ cm resistivity were amorphized from the surface down to a depth of about 440 nm wit...