Experimental Demonstration of Single Electron Transistors Featuring SiO2 PEALD in Ni-SiO2-Ni Tunnel Junctions
Experimental Demonstration of Single Electron Transistors Featuring SiO2 PEALD in Ni-SiO2-Ni Tunnel Junctions
复制标题
Ni-SiO2-Ni 隧道结中采用 SiO2 PEALD 的单电子晶体管的实验演示
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
G. Snider
中科院分区：
文献类型：
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作者：
G. Karbasian;Michael S. McConnell;A. Orlov;S. Rouvimov;G. Snider
我们报告使用等离子体增强原子层沉积（PEALD）制造单电子晶体管（SET）具有超薄（~1 nm）隧道透明的二氧化硅在Ni-SiO2-Ni隧道结。我们表明，作为一个结果的O2等离子体步骤在PEALD的SiO2，下面的Ni电极的顶面被氧化。另外，上部Ni层的底表面在其与沉积的SiO2接触的地方也被氧化，这很可能是SiO2表面上的含氧物质的结果。由于NiO的这些表面寄生层的存在，其表现出典型的热激活传输的特征，Ni-SiO2-Ni隧道结的电阻急剧增加。此外，传输机制从量子隧穿通过电介质势垒的一个一致的热激活电阻串联隧道结。因此，需要将NiO还原为Ni以恢复结的金属-绝缘体-金属（MIM）结构。快速热退火中的形成气体环境中的温度升高，作为一种技术，以减少寄生氧化层。这种方法对于依赖于具有超薄势垒的MIM隧道结的器件具有很大的意义。使用这种技术，我们成功地制造了MIM设置与最小的寄生NiO组件的痕迹。我们证明了纳米隧道结中的隧道势垒的性质可以通过SET的电学特性来评估。
We report the use of plasma-enhanced atomic layer deposition (PEALD) to fabricate single-electron transistors (SETs) featuring ultra-thin (~1 nm) tunnel-transparent SiO2 in Ni-SiO2-Ni tunnel junctions. We show that as a result of the O2 plasma steps in PEALD of SiO2, the top surface of the underlying Ni electrode is oxidized. Additionally, the bottom surface of the upper Ni layer is also oxidized where it is in contact with the deposited SiO2, most likely as a result of oxygen-containing species on the surface of the SiO2. Due to the presence of these surface parasitic layers of NiO, which exhibit features typical of thermally activated transport, the resistance of Ni-SiO2-Ni tunnel junctions is drastically increased. Moreover, the transport mechanism is changed from quantum tunneling through the dielectric barrier to one consistent with thermally activated resistors in series with tunnel junctions. The reduction of NiO to Ni is therefore required to restore the metal-insulator-metal (MIM) structure of the junctions. Rapid thermal annealing in a forming gas ambient at elevated temperatures is presented as a technique to reduce both parasitic oxide layers. This method is of great interest for devices that rely on MIM tunnel junctions with ultra-thin barriers. Using this technique, we successfully fabricated MIM SETs with minimal trace of parasitic NiO component. We demonstrate that the properties of the tunnel barrier in nanoscale tunnel junctions can be evaluated by electrical characterization of SETs.