Tunnel junctions, single electron transistors and superconducting resonators are fabricated using ultra-high vacuum metals’ deposition and in situ low energy plasma processing. These devices are then measured at cryogenic temperatures as precursors to more complex hybrid quantum devices incorporating MOS (metal-oxide-semiconducting) qubits. In particular, devices utilizing aluminum oxides (AlOx) formed in ultraclean environments with plasma oxidation exhibit reduced densities of defects promising for use in quantum devices. Ongoing work is focused on making simplified semiconductor qubits as diagnostic or benchmarks for refinement of materials and designs to inform more advanced quantum processing devices. Additionally, new directions for coupling qubits between paradigms is being pursued, e.g., MOS-dopant, MOS-superconducting and MOS-optical coupling schemes.