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Open Access Nano Express

Metal silicide/poly-Si Schottky diodes for uncooled microbolometers

Kirill V Chizh1*, Valery A Chapnin1, Victor P Kalinushkin12, Vladimir Y Resnik1, Mikhail S Storozhevykh1 and Vladimir A Yuryev12*

Author affiliations

1 A M Prokhorov General Physics Institute of the Russian Academy of Sciences, A M Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov Street, Moscow, 119991, Russia

2 Technopark of GPI RAS, Moscow, 119991, Russia

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Citation and License

Nanoscale Research Letters 2013, 8:177  doi:10.1186/1556-276X-8-177

Published: 17 April 2013

Abstract

Nickel silicide Schottky diodes formed on polycrystalline Si 〈P〉 films are proposed as temperature sensors of monolithic uncooled microbolometer infrared focal plane arrays. The structure and composition of nickel silicide/polycrystalline silicon films synthesized in a low-temperature process are examined by means of transmission electron microscopy. The Ni silicide is identified as a multi-phase compound composed of 20% to 40% of Ni3Si, 30% to 60% of Ni2Si, and 10% to 30% of NiSi with probable minor content of NiSi2 at the silicide/poly-Si interface. Rectification ratios of the Schottky diodes vary from about 100 to about 20 for the temperature increasing from 22℃ to 70℃; they exceed 1,000 at 80 K. A barrier of around 0.95 eV is found to control the photovoltage spectra at room temperature. A set of barriers is observed in photo-electromotive force spectra at 80 K and attributed to the Ni silicide/poly-Si interface. Absolute values of temperature coefficients of voltage and current are found to vary from 0.3%℃ to 0.6%/℃ for forward bias and around 2.5%/℃ for reverse bias of the diodes.

Keywords:
Ni silicide; Poly-Si; Schottky diodes; Temperature sensors