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Project

Nano-Electro-Mechanical Relays (Design, Fabrication, and Characterization)

Classical CMOS device downscaling has been faced with major issues since we reached the sub-100nm technology. The challenges are mainly due to an exponential increase of the leakage current with decreasing threshold voltage Vt due to a finite sub-threshold slope. This leakage current increase has caused Vt scaling to slow down, which in turn has slowed down the scaling of supply voltage, VDD. As a result both the active power, related to VDD2, and the standby power, related to VDD multiplied with the leakage current per unit area increase considerably. Due to these issues many researchers’ interest were drawn to find and demonstrate new switching concepts which have a much steeper subthreshold slope in their I-V characteristics. NanoElectroMechanical (NEM) Switches are among the most interesting devices due to their near zero leakage current and abrupt switching characteristics, resulting in a high on-current/off-current ratio.  Also the stand-by power consumption of the switch decreases dramatically.

This work includes design, fabrication and characterization of NEM ohmic switches using a proposed CMOS compatible process flow which was based on low temperature ultrathin poly-SiGe layers in 200mm pilot line.

This work includes some analytical modeling and FEM simulations of an ohmic switch. The effect of the dimensions of each structural parameter and of the material properties on the main switching parameters is investigated. Both the pull-in voltage, which determines the supply voltage of the device, and the switching time, which is related to the speed of the switch, are studied.

Releasing of such a small and thin structures without irreversible stiction was a challenge for the fabrication part which was successfully developed. Several devices with variation on dimensions were fabricated using this thin film technology and were electrically characterized to investigate the basic switching behavior of the device versus its size and also to investigate how to improve the reliability of the such a small devices to be able to integrate them with CMOS circuits.

Date:6 Sep 2011 →  19 Dec 2018
Keywords:Nano-Electro-Mechanical Switch
Disciplines:Nanotechnology, Design theories and methods
Project type:PhD project