Achieving uniform and scalable control of semiconductor spin qubits remains a key challenge for large scale quantum computing. In this work, we investigate how gate oxide thickness influences uniformity in dense two dimensional silicon quantum dot arrays. Using a 7 x 7 array fabricated in a 300 mm CMOS-process patterned by EUV lithography, we statistically characterize 392 quantum dots across four different oxide thicknesses. The threshold voltages, capacitances, lever arms, and charging energies are extracted using parallel row based measurements and we identify an optimal SiO2 thickness of 17 nm that minimizes threshold voltage variability below 63 mV standard deviation. Our observations illustrate how multiple sources of disorder can introduce competing oxide-thickness dependencies, resulting in non-monotonic trends. These results provide key design guidelines for dense, scalable silicon spin qubit architectures.
@article{arxiv.2605.12143,
title = {Understanding oxide-thickness-dependent variability in dense Si-MOS quantum dot arrays},
author = {Arne Loenders and Jacques Van Damme and Clement Godfrin and Paola Favia and Jacopo Franco and Thomas Van Caekenberghe and Bart Raes and Gulzat Jaliel and Sylvain Baudot and Luis Francisco Pinotti and Alexander Grill and George Simion and Kristof Moors and Vukan Levajac and Sofie Beyne and Sugandha Sharma and Stefan Kubicek and Yosuke Shimura and Roger Loo and Massimo Mongillo and Danny Wan and Kristiaan De Greve},
journal= {arXiv preprint arXiv:2605.12143},
year = {2026}
}
Comments
20 pages, 1 table, 4 main text figures and 8 appendix figures