| The present work investigates the synthesis of p-FeSi2 and p-Fe(C,SD2 films by MEVVA ion implantor (Metal Vapor Vacuum Arc Ion Source) and their characterization by TEM, HREM, GAXRD, and photon absorption methods.By adjusting implantation energy, dosage, and annealing temperature, (3-FeSi2 films with different thickness and morphology were obtained. The as-implanted samples contain y phase, p phase, or amorphous phase, depending on theUiipixuii.cunj.ii paidiiiCKaS. wiiCIl the energy ttliu uu&agt, iiac LU uurvv oiiu4xl017ions/cm2, amorphous layer is formed directly, which transforms into fine p-FeSi2 grains after crystallization. The phase formation sequence upon increasing temperature is y-FeSi2 -?-FeSi2 - a-FeSi2, CsCl-FeSi2 -? -FeSi2 -a-FeSi2, ?-FeSi2 -a-FeSi2, or amorphous - ?-FeSi2 - a-FeSi2, depending on the initial states. The annealing also changes the grain morphology. The p grains from the amorphous layer are finer than in the other cases. Silicide grains grow towards the substrate at high annealing temperature and finally shrink into isolated islands, thus deteriorating the silicide/Si interface smoothness. The buried layers moves towards sample surface, forming surface layers. The implantation-damaged zone also moves towards the surface and is recovered gradually.The Fe-implanted films were implanted, or doped, with small amount of Carbon for improving the film quality. TEM Analysis demonstrates that the film quality is indeed improved as manifested by smoother ?-FeSi2/Si interface, more homogeneous film thickness, finer grains, and higher thermal stability. Further analysis by photon absorption measurements reveals that the bandgap value Egd is not significantly altered. Therefore, Carbon dosage is favorable for obtaining high-quality ?-FeSi2 films. We also show that preparation methods, working parameters, substrate orientation, the type and amounts of doped ions, and annealing temperature are all exerting influences over Egd. This is why different Egd values are reported in literatures. In addition, amorphous initial state is not sensitive to Carbon dosage.An accurate measurement of lattice constants of the P films were carried out by GAXRD. The lattice constants were refined using Celref program. When implanted C/Fe ions ratio is 0.5%, the P lattice is expanded, though C atom is much smaller han Si. This is probably due to the solid solution in interstitial state. Further ncrease in C content leads to lattice contraction, due to the solid solution in ubstitution mode, i.e. replacing Si in the P structure.After a detailed investigation on the p-FeSi2/Si orientation relationships by CEM, we point out that the existence of several competing and incoherent rientation relationships, twining, and lattice mismatch are responsible for the ifficulty in obtaining high-quality p-FeSi2 films.For the sake of further understanding the p-FeSi2/Si orientation relationships, e calculate the orientations by grain boundary orientation theory. The best P-FeSi2/Si orientation relationship is situated in the vicinity of (100)p// (100)si, [010]p// 011>Si, with small angular deviations for adapting to the lattice mismatch. The attice parameter change due to heat treatment and C doping does not alter this ptimum orientation relationship but only slightly adjust the deviation angles. The alculated angles between (111)s, and (110)p all is 4皛6?for the lattice parameters neasured. Once projected along [001]p or [0-11]sj, the planes (111)si and (110) p have early 4?angle as confirmed by HREM. We also show that no planes with low idices between the two lattices are parallel. Therefore, epitaxy growth on (100)sj corresponding to (100)p), or (111)Sl (corresponding to (110) p) would be very ifficult under the optimum orientation relationship because of the slight but efinitely present deviation angles.
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