Enhancement-mode buried strained silicon channel quantum dot with tunable lateral geometry

We propose and demonstrate a relaxed-SiGe/strained-Si enhancement-mode gate stack for quantum dots. A mobility of 1.6 × 105 cm2/Vs at 5.8 × 1011/cm2 is measured in Hall bars that witness the same device process flow as the quantum dot. Periodic Coulomb blockade measured in a double-top-gated lateral quantum dot nanostructure terminates with open diamonds up to ±10 mV of dc voltage across the device. The devices were fabricated within a 150 mm Si foundry setting that uses implanted ohmics and chemical-vapor-deposited dielectrics. A modified implant, polycrystalline silicon formation and annealing conditions were utilized to minimize the thermal budget that potentially leads to Ge/Si interdiffusion.