Vertically Integrated Silicon Carbide/Silicon Detectors for UV/Vis Multicolor Sensing

We propose to design and fabricate vertically-integrated Silicon Carbide/Silicon (SiC/Si) detectors for high-responsivity and performance Ultraviolet/Visible (UV/Vis) sensing in the ~200 to 1100 nm range. We will initially stack single sensors and integrate them with readout circuitry into a single package. The development effort will include identifying the design requirements for individual sensors, fabricating a custom SiC UV sensor for the purpose, developing and demonstrating the integration scheme (including stacked chip assembly techniques and packaging and lid selection), and readout circuit development and integration. The effort will also include a feasibility study and roadmap creation for our plans to scale this design to stacking sensor arrays into a detector system for e.g. spectroscopic applications, with significant enhancements to NASA’s capabilities in planetary science, Earth science, astrophysics, and heliophysics. Two-color detectors are typically used for measurement applications requiring increased spectral range and comprise one photodiode (for shorter-wavelegnth light) mounted over a second photodiode (for longer wavelengths). In the SiC/Si system, this requires the SiC sensor to be above the Si sensor, since SiC is transparent to visible light. The two-color sensor and detector concept allows measurements and detection in broader wavelength ranges with a more compact device. Target commercial markets include defense applications (such as rocket plume detection), biological and health applications (such as sterilization, water purification, laser surgery monitoring and feedback), industrial applications (flame detection, combustion control), semiconductor fabrication equipment applications, and metrology.
Benefits: The Large UV/Optical/IR Surveyor, LUVOIR, plans for a multi-spectral sensor platform. Some proposed instrument concepts center on high-sensitivity, low-noise, rad-hard UV/Vis sensor technologies that can be scaled up to large formats. This study has contributed to the conception and instrument assessments of the Habitable Worlds Observatory (HWO). In Earth Science, UV/Vis spectral measurements can be a significant tool in detecting trace gases and pollutants such as NiO2, formaldehyde, and O3. In Planetary Science, this type of atmospheric characterization has several applications. Missions focusing on the study of the presence of water on the Moon and other solar system bodies would greatly benefit from the ability to detect hydroxyl and water signatures in the Near UV range (between 250 and 350 nm) simultaneously with visible monitoring. The Lunar Trailblazer mission and potential future versions, or similar missions to other solar system bodies, under the SIMPLEx program, have surface characterization targets. The ability to expand instrumentation capabilities from UV to UV/Vis should help increase the capabilities of miniaturized instrumentation, such as those required by Cubesats. There are also other missions in conceptual development, such as the Triton Ocean World Surveyor, which require both ultraviolet and visible spectroscopy and imaging applications. Potential successors to NASA’s MESSENGER (which included a UV/Vis spectrometer in its Mercury observations, detecting the presence of exospheric magnesium, manganese, and very high temperature calcium) can similarly help characterize surface weathering, mineralogy, atmospheric compositions, and changes through time by the use of UV/Vis spectroscopy. The Cosmic Origins Program is currently in the planning stages for a UV-optical successor to Hubble Space Telescope for the next generation telescope imaging systems, as the James Webb ST covers the visible and IR parts of the spectrum. A short summary of applications for UV/Vis sensing, spectroscopy and imaging include: In biological and health applications, sanitation (e.g. water/air sterilization system monitoring) and laser surgery feedback and power control; in defense and safety applications, rocket plume, fire, trace gas, and bio-threat detection; in industrial applications, combustion control, flame and plasma detection, industrial monitoring, high-resolution fault inspection, and UV source calibration; in semiconductor fabrication equipment, feedback and power control for the UV lasers, and in metrology, UV interferometry. There are also instrumentation design applications and calibration requirements for UV sources. There are numerous applications across a range of scientific and technical fields that can make use of advanced UV/Vis detection capabilities in the laboratory and field. UV/Vis spectroscopy has applications in chemical characterization and analysis, impurity detection, reaction monitoring, and forensic analysis.