Wendoloski, J. P.J. P.WendoloskiHillier, J.J.HillierLiles, S. D.S. D.LilesRendell, M. J.M. J.RendellAshlea-Alava, Y.Y.Ashlea-AlavaRaes, B.B.RaesLi, R.R.LiKubicek, S.S.KubicekGodfrin, C.C.GodfrinJussot, JulienJulienJussotBeyne, SofieSofieBeyneWan, DannyDannyWanRahman, Md. M.Md. M.RahmanYianni, S.S.YianniChan, K. W.K. W.ChanHudson, F. E.F. E.HudsonLim, W. H.W. H.LimDe Greve, KristiaanKristiaanDe GreveDzurak, A. S.A. S.DzurakHamilton, A. R.A. R.Hamilton2026-05-072026-05-0720262469-9950https://imec-publications.be/handle/20.500.12860/59368The quality of the silicon-oxide interface plays a crucial role in fabricating reproducible silicon spin qubits. In this work we characterize interface quality by performing mobility measurements on silicon Hall bars. We find a peak electron mobility of nearly 40000cm2/Vs in a device with a 21nm oxide layer, and a peak hole mobility of about 2000cm2/Vs in a device with 8nm oxide, the latter being the highest recorded mobility for a p-type silicon MOSFET. Despite the high device quality, we note an order-of-magnitude difference in mobility between electrons and holes. By studying additional n-type and p-type devices with identical oxides, and fitting to transport theory, we show that this mobility discrepancy is due to valence band nonparabolicity. The nonparabolicity endows holes with a density-dependent transverse effective mass ranging from 0.6⁢𝑚0 to 0.7⁢𝑚0, significantly larger than the usually quoted band-edge mass of 0.22⁢𝑚0. Finally, we perform magnetotransport measurements to extract electron momentum and quantum scattering lifetimes.engJournal article10.1103/g29w-st3qWOS:001686763000003INVERSION-LAYERS