Integrated SiC Photodiode Arrays for UV-Spectroscopic Applications

We propose to design and fabricate passive and active SiC UV linear sensor arrays, to build upon and scale up our technology for the eventual fabrication of 128x2 SiC active UV sensor arrays with lt;40 um pitch, with the first stage of the readout circuit integrated on the same chip, next to the sensors themselves, to minimize parasitic effects. The circuit design will use external signals to reset the photodiodes, buffer the output signal, and let diode selection for read-out by multiplexing. Building upon our background, we will demonstrate 128x2 arrays in an aspect ratio suitable for future spectroscopic use, and incorporate deep trenches for electrical isolation between neighboring pixels. We will also demonstrate 8x2 active arrays in a similar aspect ratio, integrating the first readout circuit stage (a 3T pixel circuit) next to the sensors themselves. We will layout and fabricate pn-junction and Schottky diodes with a range of designs for sensitivity in the target spectral range. We will also optimize each 3T circuit transistor at the semiconductor device level, tailoring their electrical characteristics to their role in the circuit, with the trade-offs between size, threshold voltage, current drive and leakage. The diodes, transistors, and the circuit architecture all will be co-optimized self-consistently. Looking forward, we will design for a 40-mu;m pitch pixel with the 3T readout circuit integrated within the pixel itself. This work enjoins the unique advantages of SiC, such as its low dark current at high temperatures, its inherent visible-blindness, and its capability to grow a native oxide, to the advantages of active pixel sensor technology such as higher sensitivity and low power consumption, to revolutionize UV sensing in the 120 to 350 nm range. This opens up a way to the development of advanced, flexible instrumentation with lower design complexity for applications in spectroscopy, remote sensing and characterization, and imaging.