Description: Superconducting films of magnesium diboride (MgB2) are very attractive for a range of detector and telecommunications applications owing to the high critical temperature of these films, ~40 K, which greatly simplifies the cooling requirements. We propose to develop a reactive evaporation technique for the deposition of MgB2 thick films on wafers up to at least 4" diameter, and an etch back and passivation process to produce high-quality thin films that are needed for the development of superconducting single photon detectors (SNSPDs) and THz hot electron bolometer (HEB) mixers. Currently there is no domestic commercial source for MgB2 films; the only commercial source we are aware of is an overseas vendor that can supply films only on very small (<1 cm2) chips. In Phase I, we demonstrated the feasibility of the etch back and passivation process, and completed designs for the reactive evaporation system that we will build in Phase II and develop a wafer-scale process for the deposition and production of MgB2 films.

Benefits: All NASA space missions are supported by Space Communication and Navigation (SCaN) technologies that provide the command, telemetry, science data transfer, and navigation support required for these missions. In view of NASA's commitment that "communications shall enable and not constrain missions," there is a recognized need for new and innovative technologies for free-space, long-range optical communications that will enhance downlink and uplink data transfer rates for space missions and provide increased security for future manned missions that could be jeopardized through cyberattacks. There has been significant interest in single photon detectors based on MgB2 films to meet these needs, and in THz HEB mixers based on MgB2 films for future astrophysics applications, such as for the Far-IR Surveyor mission or for SOFIA heterodyne instruments.

High-quality MgB2 films are attractive for a number of superconducting electronics applications, and the availability of internal MgB2 deposition capabilities would enable the company to broaden the range of services and products currently offered. Potential non-NASA commercial applications include custom fabrication of microwave devices that can take advantage of the low surface resistance of MgB2 films; the development of SQUID sensors to augment the company's existing LTS and HTS SQUID product line for applications in biomedical imaging, non-destructive testing of materials and geophysical exploration; and the fabrication of flexible cryogenic interconnects for LTS computing.