Gauss theorem
It can be the memory: the electric field intensity equal to flux, the flux through the electric field lines is the number of the passes is equal to the amount of charge per unit area divided by ε
There Poisson equation: Poisson equation is the amount of simplified equation Laplace equation takes zero time, is the second derivative of the voltage, the first derivative of the electric field is equal to the electric flux.
Sub-threshold current: when the source-drain voltage lower than the threshold voltage, the channel is in the off state at this time, but still a leakage current between the source and the drain, this current is called sub-threshold current, off-state leakage current is. Subthreshold current relationship between the gate length and gate width are,
Ids=100 W/LEXP(q(vgs-vt))/kt)
The threshold voltage is not too low, or leakage current increases, the channel length decreases the threshold voltage will fall. Vt = Vt-long - (Vds + 0.4) * EXP (-L / ld)
ld is DIBL characteristic length L needs to be reduced to reduce ld, is necessary to reduce Tox Wdep Xj
Transconductance g = Ids / Vgs generally desirable better.
