Germanium Spherical Quantum-Dot Single-Hole Transistors With Self-Organized Tunnel Barriers and Self-Aligned Electrodes

作者：Chi-Cheng Lai, Rong-Cun Pan, I-Hsiang Wang, T. George, Horng‐Chih Lin, Pei-Wen Li · 发表于：IEEE Journal of the Electron Devices Society · 年份：2023 · DOI：10.1109/jeds.2023.3235386 · 被引用次数：10 · 研究领域：Semiconductor Quantum Structures and Devices、Quantum and electron transport phenomena、Semiconductor materials and devices

We report the fabrication and electrical characterization of single-hole transistors (SHTs), in which a Ge spherical quantum dot (QD) weakly couples to self-aligned electrodes via self-organized tunnel barriers of Si3N4. A combination of lithographic patterning, sidewall spacers, and self-assembled growth was used for fabrication. The core experimental approach is based on the selective oxidation of poly-SiGe spacer islands located at the specially designed included-angle locations of Si3N4/Si-trenches. By adjusting processing times for conformal deposition, etch back and thermal oxidation, good tunability in the Ge QD size and its tunnel-barrier widths were controllably achieved. Each Ge QD is electrically addressable via self-aligned Si gate and reservoirs, thus offering an effective building block for implementing single-charge devices.