Ozark Integrated Circuits, Inc.
Fayetteville, Arkansas, USA
Abstract— The work described herein applies a patented integrated silicon carbide (SiC) bipolar junction transistor (BJT) to the detection of ultraviolet (UV) light in situ for extreme-temperature environments. An integrated SiC BJT provides four important capabilities for UV detection in extreme environments: (1) The miniaturization of detectors and readout circuits through micron-scaled integrated circuit (IC) lithography; (2) the high-temperature operation of SiC ICs; (3) long-term reliability of SiC at high temperatures; and (4) the deep-UV responsivity of 4H-SiC. The design, manufacture and electrical characterization of a SiC photo-transistor is described. Photonic characterization of the photo-transistor responsivity in the vacuum ultraviolet (VUV) and near UV is analyzed. It will be shown that integration of the photo-transistor with SiC CMOS advances the state-of-the-art to a photo-BiCMOS capability. The advancement of the state of the art is validated in both terrestrial and space-born applications, specifically (1) the patent-pending detection of the ultraviolet signature produced by the charge-compression auto-ignition of diesel fuel in a working 4-stroke engine, and (2) the measurement of Solar UV intensity in Low-Earth Orbit (LEO).
Keywords—SiC, BiCMOS, photo-transistor, ultraviolet, characterization, stratified charge-compression auto-ignition, low-Earth orbit