Establishment of the Negative-Ion Beam Technology for Material Modification

1.大电流负离子源和负离子注入机的研制：(1)研制了一台强射频等离子体溅射型重负离子源(RFNIS)，它可以以直流方式输出几毫安的B、P、Si、C等半导体制造所需的各种元素的强流负离子束。我们还研制了一台配备了小型RFNIS的中电流型负离子注入机，其中的清洁室使离子在清洁条件下和在实际注入过程中都能被注入。2.负离子注入过程中衬底充电现象的研究。(1)我们发现负离子注入时孤立电极的充电电压只有几伏正。这种低电压的充电机制是由于发射的电子以低能量返回的结果。(2)通过对二次e…的分析，提出了一种测量绝缘子表面充电电压的新方法。更详细的电子能量分布表明，负离子注入绝缘子的充电电位为负几伏。3.负离子注入器件的评价通过对负离子注入后栅氧化层的测试装置的评价，发现负离子注入在未来的ULSI低充电制造中是适用的。4.低能负离子束沉积薄膜的形成我们开发了一种低能量负离子束沉积系统，其中负离子束具有约10 eV的低能散。该系统对30 eV的低能束具有良好的能量可控性。沉积的低碳负离子碳膜是一种非晶态的类金刚石碳膜。5.粉末非散射注入方法的发展用正离子注入的方法从理论和实验上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无散射注入方法。较少

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