Reducing strain fluctuations in quantum dot devices by gate-layer stacking

• DOI: 10.48550/arxiv.2312.09235
• Publication Date: 2023-01-01
• Authors: Collin C. D. Frink; Benjamin D. Woods; Merritt P. Losert; E. R. MacQuarrie; Mark Friesen; M. A. Eriksson
• Keywords: Active layer; Strain (injury); Thermal fluctuations

Nanofabricated metal gate electrodes are commonly used to confine and control electrons in electrostatically defined quantum dots. However, these same gates impart a complicated strain geometry that affects the confinement potential potentially impairs device functionality. Here we investigate strain-induced fluctuations of energy Si/SiGe heterostructures, caused by (i) lattice mismatch, (ii) materials-dependent thermal contraction, (iii) deposition stress gates. By simulating different geometries, ranging from simple realistically complicated, including features like overlapping oxide layers, can explain most observed features. In particular, show be suppressed employing cover whole active region, when layers thin. These results suggest effects should not present serious challenge qubit uniformity following design rules.