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About negative bias for bottom gate


Please, forgive me for my ignorance, but I am wondering why there is no option for negative bottom gate bias. Is it not possible to run monte carlo simulation with negative gate voltage at bottom plate ?


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    Mohamed Mohamed

    For an n-channel MOSFET, generally the gate workfunction is designed to obtain a threshold voltage that is greater than zero. Hence, the device is off at zero gate voltage and there is no need to apply a negative gate bias to shut off the device. In such cases, applying a negative bias will generally not yield good statistic. This is because the MC observables (i.e. velocity, energy, current etc..) are calculated via statistical sample. The convergence is proportional to 1 / sqrt(N) (N = number of particles). Hence one may require to run the simulation for very long time to any meaningful statistic when enough particles are not present.

    Nonetheless, for this tool the user is given the option to vary the metal workfunction (and hence the threshold voltage). A negative voltage maybe used to switch of the device for cases when the device is ON at Vg = 0.

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    Mohamed Mohamed

    I suppose you are interested in a negative bias to turn-off the bottom gate. We will add the option to use negative bias to the tool for both gates.

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