Cryo-multiplexer for high throughput spin qubit device characterisation

The field of semiconductor spin qubits is moving away from small-scale demonstrators for enhancing fidelities of elementary qubit operations and is heading towards large-scale quantum chips with scalable architectures [1]. This progression drives an increase in device complexity and raises the demand for higher device homogeneity and fabrication yields. In parallel, increasing numbers of industrial foundries are starting to produce hundreds of spin qubit chips on 200 and 300 mm wafers [2,3]. In order to test a large number of complex spin-qubit devices, to measure the device yield and to identify promising candidates for further measurements, a fast method to characterise these devices close to operation temperature is inevitable [4]. The cryo-multiplexer presented here attempts to solve this issue. It enables us to measure several tens of complex qubit devices during one cooldown cycle, and thus dramatically cutting the time needed for the device characterisation. The multiplexer is built with of-the-shelf electronics and in this talk we go over the details of the design and the characterisation of the cryo-multiplexer at 4 K. Furthermore, we will show qubit device measurements geared towards benchmarking the device operability.

[1] Künne and Willmes et al., Nat. Commun. 15, 4977 (2024).

[2] Neyens et al., Nature 629, 80 (2024).

[3] Komeričkia et al., ECS Transactions 114, 133 (2024).

[4] Paquelet et al., npj Quantum Inf 6,43 (2020)