Non-invasive SOI gating of 2D electron systems on pristine hydrogen-terminated Si surfaces

Silicon has a variety of surface terminations in which surfaces states are passivated and where 2D electron or hole surface accumulation layers are possible through electrostatic gating. Because of the simplicity and high degree of perfection, we use a wet chemical treatment to terminate Si(111) surfaces with hydrogen and have developed techniques to probe 2D transport on these passivated surfaces. While other chemical terminations of different Si surfaces exist (i.e. Cl, Br, I), we have focused exclusively on H-Si(111), but are in process of extending our study to include H-Si(100) surfaces as their 2+2 valley degeneracy are more favorable platforms for quantum information processing. We are now developing techniques to probe pristine hydrogen-terminated Si(111) and Si(100) surfaces using a non-invasive SOI flip-chip gating method in which all device fabrication is performed on the SOI piece. Extremely high mobilities in excess of 300,000 cm²/Vs have been demonstrated in our devices, and further refinement of techniques to preserve the pristine nature of the terminated Si surfaces is expected to yield even higher mobilities. Architecture details and ohmic contact tests will be presented as well as ongoing low temperature device characterization measurements.