Germanium wafers for strained quantum wells with low disorder
article
We grow strained Ge/SiGe heterostructures by reduced-pressure chemical vapor deposition on 100 mm Ge wafers. The use of Ge wafers as substrates for epitaxy enables high-quality Ge-rich SiGe strain-relaxed buffers with a threading dislocation density of (6 ± 1) × 10 5 cm − 2 , nearly an order of magnitude improvement compared to control strain-relaxed buffers on Si wafers. The associated reduction in short-range scattering allows for a drastic improvement of the disorder properties of the two-dimensional hole gas, measured in several Ge/SiGe heterostructure field-effect transistors. We measure an average low percolation density of (1.22 ± 0.03) × 10 10 cm − 2 and an average maximum mobility of (3.4 ± 0.1) × 10 6 cm 2 / Vs and quantum mobility of (8.4 ± 0.5) × 10 4 cm 2 / Vs when the hole density in the quantum well is saturated to (1.65 ± 0.02) × 10 11 cm − 2 . We anticipate immediate application of these heterostructures for next-generation, higher-performance Ge spin-qubits, and their integration into larger quantum processors.
TNO Identifier
988970
Source
Aplied physics letters, 123
Article nr.
092101
Collation
6 p.