DEVELOPMENT OF SINGLE-ELECTRON-TRANSISTOR

基于超小隧道结库仑阻塞现象的单电子器件是纳米/埃时代超大规模集成电路中很有前途的基本逻辑器件。在MK-30K的极低温度下观察到了库仑阻塞现象。如果能以足够的重现性制作出约10 nm~2的极小隧道结，则很有可能实现室温单电子逻辑器件。本工作的目的是发展室温单电子器件的基本原理：(1)带反馈回路的新型逻辑电路结构；(2)基于选择性Al CVD的纳米制造技术。首先，我们开发了能够分析SET电路的蒙特卡罗模拟器。我们提出了一种新的电路结构：带反馈环的逆变器电路，带反馈环的逆变器电路可以抑制由于非共轭隧穿引起的电路不稳定。作为纳米制造技术，我们研究了选择性Al CVD技术。选择性Al-CDV技术是制备具有足够重复性的金属/绝缘体/金属超小隧道结的关键技术。我们提出了一种新的基于选择性Al-CVD的原子氢阻工艺。在原子氢阻工艺中，硅表面的单层厚端接-H被电子束曝光。被电子束照射的端基H被去除，然后表面被氧化。铝被选择性地沉积在剩余的端接H区域上。利用这种原子抗氢工艺，我们成功地在硅表面上制备了铝图案和铝线。

Single electron devices based on Coulomb blockade phenomena in ultrasmall tunnel junctions are promising candidates of elemental logic devices in nanometer/angstrom-era's ULSI.Coulomb blockade phenomena has been observed at very low temperatures of mK-30K range. If the very small tunnel junctions of about 10nm^2 are fabricated with sufficient reproducibility, there is great possibility of room-temperature single electron logic devices. The aim of this work is to develop fundamentals of room-temperature single electron devices : (1) a new logic circuit configuration with feed-back loop and (2) nano fabrication technology based on selective Al CVD.At first, we have developed Monte Carlo simulator which can analyze the SET circuit. We have proposed a new circuit configuration ; the inverter circuit with feed-back loop, With the feed back loop, the circuit instability due to the atochastic tunneling is found to be suppressed.As nanometer fabrication technology, we have investigated selective Al CVD technology. The selective Al-CDV technology is a key technology to fabricated metal/insulator/metal ultrasmall tunnel junctions with sufficient reproducibility. We have proposed a new atomic hydrogen resist process based on the selective Al CVD.In the atomic hydrogen resist process, monolayr thick terminated-H on Si surface is exposed by the electron beam. The terminated-H which is irradiated by the electron beam is removed and then the surface is oxidized. Aluminum is selectively deposited on the remaining terminated-H area. Using this atomic hydrogen resist process, we have successfully fabricated the Al pattern and Al wires on Si surface.