AlGaN-on-Si-Based 10- Pixel-to-Pixel Pitch Hybrid Imagers for the EUV Range

IEEE Electron Device Letters (Impact Factor: 2.79). 12/2011; DOI: 10.1109/LED.2011.2163615
Source: IEEE Xplore

ABSTRACT We report on the fabrication of extreme ultraviolet (EUV) hybrid imagers with backside-illuminated detector chip based on aluminum gallium nitride (AlGaN) layers grown on silicon and integrated with CMOS readout chip. The focal plane array (FPA) size is 256 × 256 pixels with 10-μm pixel-to-pixel pitch. The devices were characterized at wavelengths from 300 down to 1 nm using synchrotron radiation. An upper cutoff wavelength of 280 nm was observed, as expected from the AlGaN active layer composition (40% Al). Thus, the imagers have a high rejection ratio of the near UV and visible radiation. Moreover, no degradation due to proton irradiation was observed for 60-MeV energy and 5 ·1010 protons/cm2 dose. Furthermore, devices with thin silicon substrate layer that is intentionally left were fabricated, and response only in the EUV range was observed. These results demonstrate the possibility of achieving high-resolution EUV imaging with AlGaN-based FPAs, which is very promising for high-end industrial, scientific, and space applications.

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