As is known, there is trend toward miniaturization of electronic products such as mobile phones, tablets, digital cameras, and the like. There is also a demand for development of electronic products which have an increased number of functionalities and have increased electronic capabilities (e.g., increased speed, memory, and operational life). These trends have resulted in a demand for integrated circuits which enable these and other increased capabilities (e.g., increased density, computing power and extended operational life).
In particular, the foregoing trends drive a need for integrated circuits which utilize superconducting materials and properties (so-called “superconducting integrated circuits”). Superconductor materials have substantially no electrical resistance below a certain critical temperature, which may provide for increased performance in integrated circuit devices. The foregoing trend and demand also drives a need for low-loss superconducting integrated circuits and interconnect structures which enable assembly of superconducting integrated circuits.
As is also known, superconducting quantum circuits are a leading candidate technology for large-scale quantum computing. Long coherence times compared to logic gate times are necessary for building a fault tolerant quantum computer. In the case of superconducting quantum bits (qubits), coherence time improvements are attributable to a number of design changes for specific superconducting materials.
One indicator of the coherence time of a quantum integrated circuit is intrinsic quality factor Qi. Titanium nitride (TiN) superconducting coplanar waveguide (SCPW) resonators may be provided having high intrinsic quality factors Qi. Although many studies have been done on qubits, a major technical challenge is the lack of existing high performance materials, which meet the stringent requirements of qubit applications. Such requirements include: providing materials having a high intrinsic quality factor, keeping a substantially stoichiometric thin film composition across a wafer, wafer-to-wafer reproducibility, and stability over milli-Kelvine temperature range in addition to the mandatory requirements of scalability.