Research on Functional Devices Utilizing Single Electron Tunneling Phenomena

(1)使用Monte Carlo电路模拟器，我们研究了各种器件结构与使用单电子隧穿（SET）现象。隧道电阻的减小对于保证SET器件的高电流驱动能力是必要的，但由于共隧道效应导致电路故障。我们证明了存在一个合适的隧道值依赖于电路规模。(2)我们提出了一个SET器件的缩放规则。虽然电容器的缩小导致漏电流和施加电压的增加，但我们发现由于焦耳热引起的结温升高可能会阻止它们的正常工作。(3)我们证明，“多电子”逻辑，而不是“单电子”是适合于稳定的设置电路操作，因为在一个相当大的负载电容器的电子屏幕电子在一个控制节点，这是由反相器链电路的模拟确认的电子电荷。我们发现，最好的负载电容器将是一个“15电子”的逻辑从开关时间和功耗之间的权衡点。(4)我们建立了利用电子束直写在GaAs/AlGaAs异质结上制作SET器件的基本工艺技术。

(1) Using a Monte Carlo circuit simulator, we investigated various device structures with the use of single electron tunneling (SET) phenomena. The decrease of tunnel resistance is essential to ensure high current drivabiltiy of SET devices but leads to circuit malfunctions due to co-tunneling effect. We demonstrated that there exists a suitable tunneling value depending on circuit scale.(2) We proposed a scaling rule for SET devices. Although the down-scaling of capacitors results in the increase of drain current and applied voltage, we showed that junction-temperature-rise due to Joule heat may prohibit their normal operation.(3) We demonstrated that "multi-electron" logic instead of "single-electron" is suitable for stable SET circuit operation since electronic charge in a rather large load capacitor screens electron in a control node which is confirmed by simulations of inverter chain circuits. We found that the best load capacitor would be a "15-electron" logic from a view point of a trade-off between switching time and dissipation power.(4) We established basic process technologies utilizing our EB direct writing to fabricate SET devices on GaAs/AlGaAs hetero-structures.