Polycrystalline silicon nanowires synthesis compatible with CMOS technology for integrated gas sensing applications

International audiencePolysilicon nanowires are synthesized following a classical top-down approach using conventional UV lithography technique fully compatible with the existing silicon CMOS technology. N- and P-type in-situ doping of these nanowires is controlled over a large range of doping levels and electrical properties of these nanowires are analyzed. Results show that resistivity dependence with the doping level is both related to the nanowires size dependent structural quality and doping specie. Charged gas species (ammonia) sensitivity of these nanowires has also been studied. In addition, feasibility of N- and P-channel polysilicon nanowires transistors is demonstrated

High rectifying behavior in Al/Sinanocrystal-embedded SiOxNy/p-Si heterojunctions

5International audienceWe examine the electrical properties of MIS devices made of Al/Si nanocrystal-SiOxNy/p Si. The J V characteristics of the devices present a high rectifying behavior. Temperature measurements show that the forward current is thermally activated following the thermal diffusion model of carriers. At low reverse bias, the current is governed by thermal emission amplified by Poole-Frenkel effect of carriers from defects located in the silicon nanocrystals/SiOxNy interfaces, whereas tunnel conduction in silicon oxynitride matrix dominates at high reverse bias. Devices exhibit a rectification ratio >104 for the current measured at V= 1V. Study reveals that thermal annealing in forming gas (H2/N2) improves electrical properties of the devices due to the passivation of defects

Polysilicon Nanowires for chemical sensing applications

International audiencePolycrystalline silicon nanowires are synthesized using a classical fabrication method commonly used in microelectronic industry: the sidewall spacer formation technique. Assets of this technological process rest on low cost lithographic tools use, classical silicon planar technology compatibility and the possibility to get by direct patterning numerous parallel nanowires with precise location on the substrate. Grounded and suspended polycrystalline silicon nanowires with a curvature radius as low as 150nm are integrated into resistors and used as gas (ammonia) sensors. Results show potential use of these nanowires for charged chemical species detection with an increase of the sensitivity with the increase of SiNWs exchange surface with the environment