Establishment of the Negative-Ion Beam Technology for Material Modification

1.大电流负离子源和负离子注入器的开发：(1)我们开发了一种强射频等离子溅射型重负离子源（RFNIS），它可以在直流模式下输送强度为几毫安的高电流负离子束，用于半导体制造所需的各种元素，如B，P，Si和c。(2)此外，我们还开发了一种中电流型负离子注入器，配备了小型RFNIS。其中洁净室使得离子在洁净的条件下以及在真实的植入过程中进行植入。负离子注入过程中衬底带电现象的研究。(1)我们发现在负离子注入时，孤立电极的充电电压仅为正几伏。揭示了这种低电压充电机制是由低能量发射电子返回的结果。(2)通过对二次电子能量分布的分析，提出了一种测量绝缘子表面充电电压的新方法，表明负离子注入绝缘子的充电电位为负几伏。此外，我们提出了一种双电层模型作为负离子注入过程中绝缘子的低充电机制。3 .负离子注入器件的评价从负离子注入后的栅极氧化物测试器件的评价来看，负离子注入在未来低充电的ULSI制造中是适用的。低能负离子束沉积形成薄膜我们开发了一种低能负离子束沉积系统，其中负离子束具有约10eV的低能量扩散。该系统对30eV的低能束流具有良好的能量可控性。此外，XPS.5还发现沉积的低碳负离子碳膜为无定形类金刚石碳膜。粉末非散射注入方法的研究进展通过正离子注入理论和实验阐明了粉末在注入过程中的散射现象。相反，即使在能量为20keV的负离子注入中，也没有产生散射。这说明负离子注入是一种非散射注入方法。少

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