Establishment of the Negative-Ion Beam Technology for Material Modification

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1.Development of High-Current Negative-Ion Source and Negative-Ion implanter :(1) We developed an intense RF plasma-sputter-type heavy negative-ion source (RFNIS) which can deliver high-current negative-ion beams in a dc-mode with an intensity of several mA of various elements required in the semiconductor fabrication, such as B,P,Si, and C.(2) Besides, we also developed a medium-current type negative-ion implanter equipped a small-type RFNIS.of which clean booth makes to implant ions in the clean condition as well as in the real implantation process.2.Investigation of Charging Phenomena of Substrates during Negative-Ion Implantation.(1) We found that the charging voltage of isolated electrodes at negative-ion implantation was only several volts positive. This charging mechanism with a low voltage was revealed to result from returning of emitted electrons with a low energy. (2) We developed a new method to measure the charging voltage of insulator surface by the analysis of secondary e … More lectron energy distribution and showed the charging potential of negative-ion implanted insulators was several volts negative. Besides, we proposed an electric double layr model as a low charging mechanism of insulators during negative-ion implantation.3.Evaluation of Negative-Ion Implanted DevicesFrom the evaluation of test devices of gate oxide after negative-ion implanted, the negative-ion implantation was found to be applicable in the future ULSI fabrication with low charging.4.Formation of This Film by a Low-Energy Negative-Ion Beam DepositionWe developed a negative-ion beam deposition system with a low energy in which a negative ion beam has a low energy spread of about 10eV.This system has a good energy controllability for the low energy beam of 30eV.Besides, the deposited a carbon film with a low carbon negative ions was found to be an amorphous diamond-like carbon film from XPS.5.Development of Non-Scattering Implantation Method into PowdersWe clarified the scattering phenomenon of powders during implantation by theoretically and experimentally with a positive ion implantation. On the contrary, even in the negative-ion implantation with an energy of 20keV,there was no scattering resulted. This shows the negative-ion implantation is non scattering implantation method. Less