Arrayed Quantum Dot Characterization in Si:P Quantum Devices

STM based hydrogen lithography is a promising architecture for fabrication of atomic-scale quantum devices. The precision of this technique allows placement of phosphorus atoms into pre-designed lithography patterns with sub-nanometer resolution to form quantum dots. Structures such as double quantum dots or arrays of dopants in Si are a promising platform for analog quantum simulation of the Fermi-Hubbard model. Design, fabrication and characterization of these devices is also useful for future multi-qubit Si:P-based quantum information processing. We present the design and fabrication of double/arrayed quantum dot devices. We compare low temperature transport measurements of the devices with a generalized Hubbard model and find it necessary to include inelastic processes. We extract inter-dot tunnel coupling of a double dot device and demonstrate interesting rectifying behavior. For devices with more than 2 dots, we found disorder is currently inevitable and is crucial to device transport properties. In our Si:P devices, gates/leads are capacitively coupled to the central dot region. Large gate ranges and linear capacitance coupling are essential to producing good finite bias spectroscopy. We will describe fabrication developments to improve device gating performance.