Importance of temperature dependence of interface traps in high-k metal gate stacks for silicon spin-qubit development

While semiconductor-based spin qubits have demonstrated promising fidelities exceeding 99.9%, their coherence time is limited by the presence of charge noise. However, fast process optimization for reduced charge noise becomes challenging due to the time-consuming nature of cryogenic measurements. Hence, this work explores low frequency analysis methods to determine interface trap densities, their temperature dependence, and correlation with observed noise levels. The herein presented results provide evidence for strong temperature dependence of the interface trap density. Moreover, good agreement is observed between charge pumping and conductance-based methods. Finally, differences in temperature dependent trends of flicker noise are observed, indicating additional influences, which need to be considered for further device optimization.