Quantum transport properties of industrial $^{28}$Si/$^{28}$SiO$_2$

Authors :: Sabbagh, D.
Thomas, N.
Torres, J.
Pillarisetty, R.
Amin, P.
George, H. C.
Singh, K.
Budrevich, A.
Robinson, M.
Merrill, D.
Ross, L.
Roberts, J.
Lampert, L.
Massa, L.
Amitonov, S.
Boter, J.
Droulers, G.
Eenink, H. G. J.
van Hezel, M.
Donelson, D.
Veldhorst, M.
Vandersypen, L. M. K.
Clarke, J. S.
Scappucci, G.
Source :: Phys. Rev. Applied 12, 014013 (2019)
Publication Year :: 2018
Abstract: We investigate the structural and quantum transport properties of isotopically enriched $^{28}$Si/$^{28}$SiO$_2$ stacks deposited on 300 mm Si wafers in an industrial CMOS fab. Highly uniform films are obtained with an isotopic purity greater than 99.92\%. Hall-bar transistors with an equivalent oxide thickness of 17 nm are fabricated in an academic cleanroom. A critical density for conduction of $1.75\times10^{11}$ cm$^{-2}$ and a peak mobility of 9800 cm$^2$/Vs are measured at a temperature of 1.7 K. The $^{28}$Si/$^{28}$SiO$_2$ interface is characterized by a roughness of $\Delta=0.4$ nm and a correlation length of $\Lambda=3.4$ nm. An upper bound for valley splitting energy of 480 $\mu$eV is estimated at an effective electric field of 9.5 MV/m. These results support the use of wafer-scale $^{28}$Si/$^{28}$SiO$_2$ as a promising material platform to manufacture industrial spin qubits.<br />Comment: 5 pages, 3 figures