Research on Functional Devices Utilizing Single Electron Tunneling Phenomena

(1)利用蒙特卡罗电路模拟器，利用单电子隧穿(SET)现象研究了各种器件结构。降低隧道电阻是保证SET器件高电流驱动能力的关键，但由于共隧道效应而导致电路故障。我们证明了存在一个依赖于电路规模的合适的隧穿值。(2)提出了一种SET器件的标度规则。虽然电容器的缩小会导致漏极电流和外加电压的增加，但我们发现焦耳热引起的结温升高可能会阻碍它们的正常工作。(3)通过对逆变器链电路的仿真，证明了在相当大的负载电容器中的电子电荷屏蔽了控制节点中的电子，所以适合于稳定的SET电路运行的是多电子逻辑而不是单电子逻辑。从开关时间和功耗之间权衡的角度出发，我们发现最好的负载电容应该是“15电子”逻辑。(4)建立了利用我们的电子束直写技术在GaAsAlGaAs异质结上制备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.