In this paper design and simulation of an improved depletion-mode n-channel nanoelectromechanical field effect transistor (NEMFET) at 300K is reported. The designed NEMFET is based on NEMS technology and fully compatible with CMOS fabrication process. A NEMFET is composed of a NEM relay and a MOSFET and comprises a movable gate and a semiconductor part, so that the flowing current is always in the semiconductor part. The nanomechanical movable gate was a bossed doubly clamped beam and simulated by COMSOL Multiphysics software and the electrical part was designed and simulated by ATLAS software. The designed NEMFET had a 25 nm length, 100 nm width and 5.2 nm thicknesses. Optimization was done by applying two 8.5 nm spaces, one between source to gate and the other between gate to drain. Simulation results show in the proposed structure, sub-threshold swing was decreased to 86 mV/dec and the Ion/Ioff ratio was increased to 8.68×104. Manuscript profile

In this paper, an operational transconductance amplifier (OTA) is designed, simulated and configured so that input dynamic range is improved by bulk-driven technique of the input transistors. The bulk-driven structure is used in the proposed OTA to stabilize the transconductance and to achieve a high linearity. By changing the control voltage and the input common-mode voltage, the voltages and currents of the circuit are changed so that the transconductance and the voltage gain are changed linearly. Also, setting a reference voltage in the circuit can greatly reduce the destructive effects of undesired changes in the circuit operation during fabrication process. The proposed OTA is designed in 180 nm CMOS technology and required only 0.5 V supply voltage. The simulation results show the OTA voltage gain is varied from 0 dB to 14.2 dB by changing the control voltage from 0 to 0.5 V. Moreover, the input common-mode voltage of the OTA can be changed in the range of 0.125 to 0.375V and without linear degradation. The proposed OTA is dissipated 250 nW and makes it suitable for low-power applications. Manuscript profile

In this paper, the electrical performance of double gate organic field effect transistor (DG-OFET) are thoroughly investigated and feasibility of the device as an efficient biosensor is comprehensively assessed. The introduced device provides better gate control over the channel, yielding better charge injection properties from source to channel and providing higher on-state current in comparison with single gate devices. The susceptibility of fundamental electrical parameters with respect to the variation of design parameters is thoroughly calculated. In particular, standard deviation and average value of main electrical parameters signify that metal gate workfunction, channel thickness and gate oxide thickness are fundamental design measures that may modify the device efficiency. The insensitivity of off-state current to the change of channel length and drain bias confirms feasibility of the device in nanoscale regime. Next, a nano cavity is embedded in the gate insulator region for accumulation of biomolecules. The immobilization of molecules with different dielectric constants in the gate insulator hollow alters the gate capacitance and results in the drain current deviation with respect to the air- filled cavity condition. It is shown that by the occupancy of whole volume of the nanogap, a maximum range of on-state current variation can be achieved. Manuscript profile

In this paper, the electrical performance of double gate organic field effecttransistor (DG-OFET) are thoroughly investigated and feasibility of the deviceas an efficient biosensor is comprehensively assessed. The introduced deviceprovides better gate control over the channel, yielding better charge injectionproperties from source to channel and providing higher on-state current incomparison with single gate devices. The susceptibility of fundamental electricalparameters with respect to the variation of design parameters is thoroughlycalculated. In particular, standard deviation and average value of main electricalparameters signify that metal gate work function, channel thickness and gateoxide thickness are fundamental design measures that may modify the deviceefficiency. The insensitivity of off-state current to the change of channel lengthand drain bias confirms feasibility of the device in the nanoscale regime. Next,a nano cavity is embedded in the gate insulator region for accumulation ofbiomolecules. The immobilization of molecules with different dielectric constantsin the gate insulator hollow alters the gate capacitance and results in the draincurrent deviation with respect to the air- filled cavity condition. It is shown thatby the occupancy of the whole volume of the nanogap, a maximum range of onstatecurrent variation can be achieved. Manuscript profile