Quantum Transport Properties of Industrial Si-28/(SiO2)-Si-28

We investigate the structural and quantum transport properties of isotopically enriched Si-28/(SiO2)-Si-28 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 oxide stack comprising 10 nm of (SiO2)-Si-28 and 17 nmof Al2O3 (equivalent oxide thickness of 17 nm) are fabricated in an academic cleanroom. A critical density for conduction of 1.75 x 10(11) cm(-2) and a peak mobility of 9800 cm(2)/Vs are measured at a temperature of 1.7 K. The Si-28/(SiO2)-Si-28 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 Si-28/(SiO2)-Si-28 as a promising material platform to manufacture industrial spin qubits.