Shared control of a 16 semiconductor quantum dot crossbar array

Fabrication

The device is fabricated on a Ge/SiGe heterostructure where a 16-nm-thick germanium quantum well with a maximum hole mobility of 2.5 × 10⁵ cm² V⁻¹ s⁻¹ is buried 55 nm below the semiconductor/oxide interface^25,40. We design the quantum dot plunger gates with a diameter of 100 nm, and the barrier gates separating the quantum dots with a width of 30 nm. The fabrication of the device follows these main steps. First, 30-nm-thick Pt ohmic contacts are patterned via electron-beam lithography, evaporated and diffused in the heterostructure following an etching step…