Ultralow-Dark-Current CdHgTe FPAs in the SWIR Range at CEA and Sofradir

• Published in: Journal of electronic materials 2012-10, Vol.41 (10), p.2686-2693
• Main Authors: Gravrand, O., Mollard, L., Boulade, O., Moreau, V., Sanson, E., Destefanis, G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cadmium telluride; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cross-disciplinary physics: materials science; rheology; Diodes; Electronics; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials; Materials Science; Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Molecular beam epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Optical and Electronic Materials; Optoelectronic devices; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solid State Physics
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-012-2181-8

We report the first results of work carried out at CEA and Sofradir to build ultralow-dark-current focal-plane arrays (FPAs) in the short-wave infrared range (SWIR) for space applications. These FPAs are designed to detect very low flux in the 2- μ m wavelength range. To this end, Sofradir has designed a source follower per detector read-out circuit (ROIC, 384 × 288, 15  μ m pitch). This ROIC has been hybridized on different HgCdTe diode configurations processed at CEA-LETI, and low-flux characterizations have been carried out at CEA-IRFU at low temperature (from 60 K to 160 K). Both ion-implanted p / n and n / p diodes have been evaluated. The metallurgical nature of the absorbing layer has also been examined, and both molecular-beam epitaxy (MBE) and liquid-phase epitaxy (LPE) have been applied. Dark-current measurements are discussed in comparison with previous results from the literature. State-of-the-art dark currents are recorded for temperatures higher than 120 K. At temperatures lower than 100 K, the decrease in dark current flattens out for both technologies. In this region, currents between 0.4 e – /s/pixel and 0.06 e – /s/pixel are reported.