Reconfigurable Germanium Quantum-Dot Arrays for CMOS Integratable Quantum Electronic Devices

We report the first-of-kind scalability and tunability of Ge QDs that are controllably sized, closely coupled, and self-aligned with control gates, using a combination of lithographic patterning, spacer technology, and self-assembled growth. The core experimental design is based on the thermal oxidation of poly-SiGe spacer islands designated at each included-angle location of designed Si3N4/c-Si ridge structures. Multiple Ge QDs with good size tunability of 7–20 nm were controllably achieved by adjusting the process times for deposition, etch back and thermal oxidation of poly-SiGe spacer islands. Our Ge QDs array provides a common platform for engineering diverse QD electronic devices with desired reconfigurability and optimizing their performance.