Device/circuit simulations of silicon spin qubits based on a gate-all-around transistor

TL;DR

This paper models the readout process of silicon spin qubits using GAA transistors, combining TCAD and SPICE simulations to demonstrate effective detection with CMOS circuits.

Contribution

It introduces a comprehensive simulation approach for spin qubit readout using GAA transistors and CMOS amplifiers, advancing quantum device integration.

Findings

Current-voltage characteristics depend on qubit spin states.

Simulations show effective readout with voltage control and sense amplifiers.

The approach enables integration of spin qubits with conventional circuits.

Abstract

We theoretically investigated the readout process of a spin--qubit structure based on a gate-all-around (GAA) transistor. Our study focuses on a logical qubit composed of two physical qubits. Different spin configurations result in different charge distributions, which subsequently influence the electrostatic effects on the GAA transistor. Consequently, the current flowing through the GAA transistor depends on the qubit's state. We calculated the current-voltage characteristics of the three-dimensional configurations of the qubit and GAA structures, using technology computer-aided design (TCAD) simulations. Moreover, we performed circuit simulations using the Simulation Program with Integrated Circuit Emphasis (SPICE) to investigate whether a readout circuit made from complementary metal--oxide semiconductor (CMOS) transistors can amplify the weak signals generated by the qubits. Our findings indicate that, by dynamically controlling the applied voltage within a properly designed circuit, the readout can be detected effectively based on a conventional sense amplifier.