We determine the energy splitting of the conduction-band valleys in two-dimensional electrons confined in silicon metal oxide semiconductor Hall-bar transistors. These silicon metal oxide semiconductor Hall bars are made by advanced semiconductor manufacturing on 300 mm silicon wafers and support a two-dimensional electron gas of high quality with a maximum mobility of 17.6×103 cm2/Vs and minimum percolation density of 3.45×1010 cm-2. Because of the low disorder, we observe beatings in the Shubnikov-de Haas oscillations that arise from the energy splitting of the two low-lying conduction band valleys. From the analysis of the oscillations beating patterns up to T=1.7 K, we estimate a maximum valley splitting of ?EVS=8.2 meV at a density of 6.8×1012 cm-2. Furthermore, the valley splitting increases with density at a rate consistent with theoretical predictions for a near-ideal semiconductor-oxide interface.

Perhaps the greatest challenge facing quantum computing hardware development is the lack of a high throughput electrical characterization infrastructure at the cryogenic temperatures required for qubit measurements. In this article, we discuss our efforts to develop such a line to guide 300mm spin qubit process development. This includes (i) working with our supply chain to create the required cryogenic high volume testing ecosystem, (ii) driving full wafer cryogenic testing for both transistor and quantum dot statistics, and (iii) utilizing this line to develop a quantum dot process resulting in key electrical data comparable to that from leading devices in literature, but with unprecedented yield and reproducibility.