Fabrication of semiconductor nano-scale structures and control of its electrical characteristics by means of quantum doping

通过单离子注入（SII）方式注入少量掺杂原子，首次尝试了对半导体器件有源区对应的精细电阻器电性能固有波动的修剪，使我们能够将掺杂离子逐一注入到精细半导体区，直到达到必要的数量。首先测量了在亚μm尺度硅电阻中每一个掺杂原子的电导增加为18 nS/原子。其次，采用常规器件制造工艺制作了亚μm尺寸的极细测试电阻器，得到了测试器件内电导的统计分布；初始电导大大偏离平均值，估计为63%。最后，根据每离子电导的实验增量，在初始电导分布的较高侧，将电导值修剪到某一值所需的单个离子的数量。结果表明，初始电导波动从63%成功地减小到13%。这一结果表明，可以通过SII逐个注入必要数量的掺杂原子来控制精细半导体区域的电学性质。通过对各种波动因素的分析，得出的数值比实验值大13%。差异较大的原因可能是单离子以0.3μm的间隔注入样品，过高估计了杂质位置的波动，而杂质位置在现实中并非随机。我们期望通过提高单离子入射的瞄准精度和SII来实现杂质位置之间更好的相关性，从而使位置波动更小。本研究首次阐明了杂质原子序数控制和杂质原子位置控制的关键问题。少

Trimming of the inherent fluctuation in electrical properties of a fine resistor which corresponds to an active region in semiconductor devices has been tried for the tirst time by implanting a small number of dopant atoms by means of single ion implantation (SII) which enables us to implant dopant ions one by one into a fine semiconductor region until the necessary number is reached. Firstly the conductance increase per one dopant atom in a sub-μm scale Si resistor was measured to be 18 nS/atom. Secondly very fine test resistors with a size of sub-μm were made by conventional device fabrication technology and the statistical distribution of conductance in the test devices was obtained. The initial conductance deviated considerably from the mean value, evaluated to be 63%. Finally based on the experimental increment of conductance per an ion, the number of single ions necessary to trim the conductance value into a certain value in the higher side of the initial conductance distribution … More was implanted to each test resistor. It was foud that the initial conductance fluctuation of 63% has been successfully reduced to only 13%. This result leads to the conclusion that the electrical properties in a fine semiconductor region can be controlled by implanting a necessary number of dopant atoms by SII in one-by-one manner. It was discovered that the value based on the analysis of various factors of fluctuation was larger than the experimental one, 13%. The reason for the large discrepancy was believed to be due to the overstimation of impurity position fluctuation in the specimens in which single ions were implanted at an interval of 0.3μm and the impurity position was not random in reality. We expect that a better correlation between impurity positions to be achieved by higher aiming precision of single ion incidence with SII would cause a smaller position fluctuation. This study clarifies an essential issue of controlling not only the impurity atom number but also their positions experimentally for the first time. Less