Highly Scalable SiC UV Imager for Earth & Planetary Science

Commercial silicon carbide (SiC)-based photonic sensors typically use p-i-n photodiode and reversed-biased Avalanche Photodiode (APD) detectors. These state-of-the-art SiC photodiodes use the wafer substrate as one node of the device, thereby making monolithic integration of the device with control or analysis circuitry difficult, if not impossible. In Phase I, Ozark IC demonstrated that its new (patent-pending) photo detecting devices are suitable for integration in SiC-based low-voltage integrated circuit processes. By virtue of their construction, the photo-generation occurs efficiently and with very high gain, and the devices have been shown to operate over a wide voltage (10-15 V) and temperature range (-170 C to 400 C measured). Ozark IC's extensive library of SiC analog and mixed-signal IP and its expertise in extreme-environment IC design have been used to create the world's first fully integrated 2-D UV imager (up to 192 x 128 at > 10 frames per second); ready for fabrication in Phase II. The imagers will be tested across a wide range of temperatures to demonstrate their applicability to planetary exploration, earth observation and astronomy applications.

The first obvious application of this technology is to one of NASA's many current and planned earth science missions that require space-borne instruments capable of measuring light in the ultraviolet (UV) spectrum. 1) For the Geo-CAPE mission, recommended by the NRC for the Decadal Survey, tropospheric ozone measurements in the UV range of 290 nm-340 nm are required. An instrument based on the proposed technique is very feasible and would offer significant advantages in performance, size and weight over a discrete SiC diode-based approach. 2) For planetary composition experiments such as ATLAS and NOW, an instrument capable of generating a faint object spectrograph in the 115 nm - 350 nm UV range is also possible using this technology. 3) For planetary exploration experiments such as the proposed Discovery and New Horizons missions which intend to image planets from orbit or as landers; such as those proposed for Venus, where the high temperature operation of the imager would be desirable.

Other non-NASA markets include Machine Vision, Disinfection, Industrial Controls, Safety, and Diagnostic/Inspection Systems. Deep UV imaging is of particular interest to semiconductor and scientific imaging markets. UV imaging for LAr neutrino detectors is also being investigated. An Innovation for Manufacturing: The application of the proposed imager to Machine Vision has major implications for increased automation of inspection tasks that are critical for nanoscale manufacturing.