Fabrication and characterisation of suspended narrow silicon nanowire channels for low-power nano-electro-mechanical (NEM) switch applications

• Suspended narrow conduction channel silicon nanowires fabricated and characterised.
• Double suspension fabrication employing tailored amorphous silicon sacrificial layer.
• Low threshold voltage electrical switching with current on/off ratio of 105.
• In-plane electromechanical pull-in consistent with finite element analysis.
• Solid technological basis for CMOS compatible low power NEMS switches.

Suspended silicon nanowires with narrow (∼10 nm) conduction channel are fabricated and characterised for further development of low power nano-electro-mechanical (NEM) switching devices using CMOS compatible fabrication. Double suspension fabrication process using an amorphous silicon sacrificial layer and xenon difluoride etching is employed for thermally-oxidised suspended Si nanowire channels. Device current–voltage characteristics demonstrate depletion mode operation of heavy doped nanowires with an on/off ratio of 105 and a threshold voltage of −1.8 V. In plane electromechanical pull-in to side gate is demonstrated and confirmed to be consistent with finite element analysis.

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