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This letter presents a single-electron injection device for position-based charge qubit structures implemented in 22-nm fully depleted silicon-on-insulator CMOS. Quantum dots are implemented in local well areas separated by tunnel barriers controlled by gate terminals overlapping with a thin 5-nm undoped silicon film. Interface of the quantum structure with classical electronic circuitry is provided with single-electron transistors that feature doped wells on the classic side. A small $0.7\times 0.4\,\,\mu \text{m}^{2}$ elementary quantum core is co-located with control circuitry inside the quantum operation cell which is operating at 3.5 K and a 2-GHz clock frequency. With this apparatus, we demonstrate a single-electron injection into a quantum dot.

This letter presents a fully integrated interface circuitry with a position-based charge qubit structure implemented in 22-nm FDSOI CMOS. The quantum structure is controlled by a tiny capacitive DAC (CDAC) that occupies $3.5\times 45\,\,\mu \text{m}^{2}$ and consumes 0.27mW running at a 2-GHz system clock. The state of the quantum structure is measured by a single-electron detector that consumes 1mW (including its output driver) with an area of $40\times 25\,\,\mu \text{m}^{2}$ . The low power and miniaturized layout of these circuits pave the way for integration in a large quantum core with thousands of qubits, which is a necessity for practical quantum computers. The CDAC output noise of 12 $\mu \text{V}$ -rms is estimated through mathematical analysis while the ≤ 0.225mV-rms input referred noise of the detector is verified by measurements at 3.4 K. The functionality of the system and performance of the CDAC are verified in a loopback mode with the detector sensing the CDAC-induced electron tunneling from the floating diffusion node into the quantum structure.