Depletion-mode Quantum Dots in Intrinsic Silicon

Sergey V. Amitonov; Paul C. Spruijtenburg; Max W. S. Vervoort; Wilfred G. van der Wiel; Floris A. Zwanenburg

doi:10.1063/1.5002646

paper

Depletion-mode Quantum Dots in Intrinsic Silicon

arXiv:1709.07361 · doi:10.1063/1.5002646

Abstract

We report the fabrication and electrical characterization of depletion-mode quantum dots in a two-dimensional hole gas (2DHG) in intrinsic silicon. We use fixed charge in a SiO $_{2}$ /Al $_{2}$ O $_{3}$ dielectric stack to induce a 2DHG at the Si/SiO $_{2}$ interface. Fabrication of the gate structures is accomplished with a single layer metallization process. Transport spectroscopy reveals regular Coulomb oscillations with charging energies of 10-15 meV and 3-5 meV for the few- and many-hole regimes, respectively. This depletion-mode design avoids complex multilayer architectures requiring precision alignment, and allows to adopt directly best practices already developed for depletion dots in other material systems. We also demonstrate a method to deactivate fixed charge in the SiO $_{2}$ /Al $_{2}$ O $_{3}$ dielectric stack using deep ultraviolet light, which may become an important procedure to avoid unwanted 2DHG build-up in Si MOS quantum bits.

Accepted to Applied Physics Letters. 5 pages, 3 figures