Description: Silicon Carbide deep UV detectors can achieve large gains, high signal-to-noise ratios and solar-blind operation, with added benefits of smaller sizes, lower operating voltages, radiation hardness, ruggedness and scalability. The design, fabrication and optimization of SiC UV APDs is challenging due to some material defects, relatively not-well modeled device operation, and very high absorption coefficients near 100nm wavelengths. These challenges can be overcome with detailed co-modeling, characterization, design and fabrication. Successfully operating SiC UV detectors are of utmost importance for astronomy, space exploration, upper atmosphere monitoring, and systems such as Non-Line-of-Sight (NLoS) communication. Through Phase I and Phase II, we propose to develop Silicon Carbide (SiC) based UV detectors for space applications. The initial target is the 100nm to 300nm wavelength range, with the peak responsivity expected to be within the 200nm-300nm interval. For the 100nm-200nm wavelength range, we will experiment with the use of an AlGaN cap-layer as the absorber and SiC as the multiplier. Phase I effort will focus on the design and detailed physics based simulation of these SiC APD structures. We will use SiC UV detectors fabricated by the GE Global Research Center and AlGaN APDs from University of Maryland for measurements and calibration.

Benefits: Deep UV detectors as well as sources are important for the semiconductor industry for lithography applications. For next generation deep submicron devices, deep UV detectors and instruments are necessary to achieve feature sizes that are comparable or less than the photon wavelength. Deep UV detectors are also one of the enabling technologies for UV Non-Line-of-Sight (NLoS) communication networks that have the added benefit of data security. Additionally, these SiC APDs can be used for flare detection in oil-wells and jet engines, and in the fields of bio-detection and radiation detection.

NASA has several applications for deep ultraviolet detectors. These range from long-range mission applications such as those for the Europa-Jupiter-Saturn Mission (EJSM) to earth-orbit missions. EJSM Applications: Radiation hardened deep UV detectors are ideal for the UV Spectrometer (UVS) scheduled to be included in the payload for the Jupiter-Europa-Orbiter (JEO) that is part of the EJSM. This project can partially satisfy the requirement of EUV+FUV (70-200nm) scan range for the JEO and the FUV+MUV (110-330nm) range for the Jupiter-Ganymede-Orbiter (JGO) Since radiation levels in the MRad range are estimated for the EJSM, the Phase II effort of this program on developing rad-hard readout electronics based on the current CoolCAD-NASA program experience with cryogenic and radiation testing of bulk and SOS devices for NASA, can prove to be very valuable. Earth Orbit Mission Applications: Deep UV detectors and associated readout electronics that is designed to be radiation hard and visible and solar blind, can be used extensively for next generation hyperspectral Earth remote sensing experiments. Deep UV detectors can be used as EUV photon counters for detecting ozone in the earth's atmosphere, and for detecting hydrogen by measuring the Lyman-alpha radiation.