Direct MBE growth of metamorphic nBn infrared photodetectors on 150 mm Ge-Si substrates for heterogeneous integration

• Published in: Journal of vacuum science and technology. B, Nanotechnology & microelectronics Nanotechnology & microelectronics, 2019-05, Vol.37 (3)
• Main Authors: Fastenau, Joel M., Lubyshev, Dmitri, Nelson, Scott A., Fetters, Matthew, Krysiak, Hubert, Zeng, Joe, Kattner, Michael, Frey, P., Liu, Amy W. K., Morgan, Aled O., Edwards, Stuart A., Dennis, Richard, Beech, Kim, Burrows, Doug, Patnaude, Kelly, Faska, Ross, Bundas, Jason, Reisinger, Alex, Sundaram, Mani
• Format: Article
• Language: English
• ISSN: 2166-2746; 2166-2754
• DOI: 10.1116/1.5088784

GaSb-based infrared (IR) photodetector structures were grown on large diameter, 150 mm, Si substrates using a multistep metamorphic buffer architecture process. A standard bulk InAsSb/AlAsSb barrier detector design with a cutoff wavelength of ∼4 μm was used as a test vehicle for this growth process. First, a Ge layer was deposited by chemical vapor deposition, creating a Ge-Si substrate for the subsequent molecular beam epitaxy growth of the remaining III–V buffer and device layers. X-ray diffraction and photoluminescence measurements demonstrated high crystal quality and excellent cross-wafer uniformity of the device epiwafer characteristics. Microscopy evaluation revealed a moundlike surface morphology with a low root-mean-square roughness value below 2 nm, suitable for focal plane array (FPA) fabrication. Large-area mesa diode test devices measured dark currents of 5 × 10−5 A/cm2 and a quantum efficiency of 60% for the Sb-detector grown on Ge–Si. The same structure was fully fabricated into a standard FPA and produced good imagery resolution with high operability. These excellent results for this first FPA manufactured from an Sb-photodetector grown on Si using this Ge-Si architecture demonstrate a promising path in the progression of Sb-IR technology as it transitions from development to next-generation, large-format IR manufacturing with an eye toward potential heterogeneous integration with silicon.