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arXiv · 2202.08090

Wafer-scale low-disorder 2DEG in $^{28}$Si/SiGe without an epitaxial Si cap

Davide Degli Esposti·Brian Paquelet Wuetz·Viviana Fezzi·Mario Lodari·Amir Sammak·Giordano Scappucci
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Abstract

We grow $^{28}$Si/SiGe heterostructures by reduced-pressure chemical vapor deposition and terminate the stack without an epitaxial Si cap but with an amorphous Si-rich layer obtained by exposing the SiGe barrier to dichlorosilane at 500 {\deg}C. As a result, $^{28}$Si/SiGe heterostructure field-effect transistors feature a sharp semiconductor/dielectric interface and support a two-dimensional electron gas with enhanced and more uniform transport properties across a 100 mm wafer. At T = 1.7 K we measure a high mean mobility of (1.8$\pm$0.5)$\times$10$^5$ cm$^2$/Vs and a low mean percolation density of (9$\pm$1)$\times$10$^{10}$ cm$^{-2}$. From the analysis of Shubnikov-de Haas oscillations at T = 190 mK we obtain a long mean single particle relaxation time of (8.1$\pm$0.5) ps, corresponding to a mean quantum mobility and quantum level broadening of (7.5$\pm$0.6)$\times$10$^4$ cm$^{2}$/Vs and (40$\pm$3) $\mu$eV, respectively, and a small mean Dingle ratio of (2.3$\pm$0.2), indicating reduced scattering from long range impurities and a low-disorder environment for hosting high-performance spin-qubits.

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Davide Degli Esposti, Brian Paquelet Wuetz, Viviana Fezzi, Mario Lodari, Amir Sammak, Giordano Scappucci. 2022-02-16. Wafer-scale low-disorder 2DEG in $^{28}$Si/SiGe without an epitaxial Si cap. https://doi.org/10.1063/5.0088576

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