Clarifying the physical origin of long-period charge fluctuations in Si fin-type quantum dots

Abstract Si quantum bits (qubits) have attracted attention as the building block of highly integrated quantum computers due to their compatibility with the modern complementary metal-oxide-semiconductor (CMOS) technology. For the practical operation of quantum computers, it is important not only to pursue the highest performance of qubits, but also to minimize their long-period instability in performance as they necessitate the frequent monitoring and calibration of parameters. With the Si spin qubits, fluctuations of performance over a period of minutes or even hours have been reported, which originate from the charge fluctuations. However, the cause-and-effect of long-period charge fluctuations in Si spin qubits has not been thoroughly discussed. This paper provides a brief overview of the Si spin qubit technology, focusing on the issue of long-period charge fluctuations, and presents our experimental results to clarify the physical origin of long-period charge fluctuations in fin-type quantum dots through random telegraph noise (RTN) characterization.