Study on suppression of fluctuation in semiconductor electrical characteristics by single ion inplantaticn

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In order to develop potentialities of single ion implantation through die precise control of solid-state physical and chemical properties in nano-scale semiconductors by one-by-one implantation of dopant atoms, we demonstrated the control of the electrical characteristics in ultrafine semiconductor devices and the selective growth of carbon nanotubes/fibers at catalytic ion-implanted site as follows.Control of electrical properties in ultrafine semiconductor devicesThe influence of dopant atom position on V_<th> in silicon wire MOSFETs was experimentally investigated for the first time by means of SIX. P single-ions were implanted into n-type channel region at intervals of 100nm. V_<th> was evaluated and compared with that of conventional FETs in which the dopant atoms were randomly introduced. Our results indicate that V_<th> fluctuation of FETs with ordered dopant distribution was smaller than that of FETs with random channel doping. It was also found that the average value of V_<th> … More of FETs with the ordered dopants was much lower than that of FETs with the random distribution of dopants, even though the dopant number was exactly same for both FETs. This indicates that it is important to control the dopant position for the precise control of V_<th>.Position control of carbon nanotubes/fibersThe precise control of individual CNFs position on substrate is essential for opening up novel device applications. We attempted to control the growth position of CNFs by means of focused Ni ion implantation and the subsequent plasma chemical vapor deposition (CVD). Ni ions were implanted at 30kV into n-type Si(100) substrate through the thermally grown oxide film. After a removal of thermal oxide, an antenna edge 2450MHz microwave plasma assistant CVD was carried out at 600℃ for 10 min with pure hydrogen and methane over 99.9999% for the CNF growth. The selective growth of CNFs on Ni-implanted sites was observed. It was confirmed for the first time that the implanted Ni ions act as a catalyst for the synthesis of CNFs. Less