The ``silicon_poisson'' system solves for psi.
The silicon_poisson system can only be used in situations in which no currents are flowing. It is most often used to obtain the initial solution at zero bias to be used in a subsequent silicon_dd calculation, for example. However, silicon_poisson can also be used with applied bias for certain structures, such as a 1-D MOS capacitor. In that case, the most convenient approach is use a different material (e.g., poly) for the gate, and then set the following dbase parameter as follows:
dbase create name="/options/modulate_qf_with_bias" sval=''poly''This dbase entry will set the fixed quasi-Fermi level of the poly equal to the bias applied to the electrode in the bias statement.
An implementation of silicon_poisson is given below:
system name=silicon_poisson
+ sysvars=psi
+ term0=ndiv_fbm.lapflux(psi|psi)@{silicon,poly,oxide}
+ term1=nodal.nscd(electrons,holes,netdope|psi)@{silicon,poly}
+ term2=dirichlet.device_dirichlet(netdope|psi)@{silicon/gate,poly/gate,silicon/back,silicon/source,silicon/drain,oxide/gate,silicon/substrate}
+ term3=constraint.continuity(psi|psi)@{silicon/oxide,poly/oxide}
+ tmpvars=electrons,holes
+ func0=quasiFermi(psi|electrons,holes)@{silicon,poly}