High breakdown voltage schottky gating of doped Si/SiGe 2DEG systems enabled by suppression of phosphorus surface segregation

Quantum dot devices in the Si/SiGe material system are a promising candidate to implement quantum computation due to the weak nature of its nuclear spin. A Schottky split-gate on a Si/SiGe modulation-doped two-dimensional electron gas (2DEG) with negative biases has become a common way to define lateral quantum dot arrays. However, the severe leakage through the Schottky gate caused by the phosphorus surface segregation from the intentionally doped electron supply layer degrades the reliability of split gate technique. In this study, we demonstrate a large reduction in gate leakage by the suppression of phosphorus surface segregation during sample growth.