Adding Ionized Dopants

In semiconductor physics, the concentration and distribution of the ionized dopants control the fermi-level. Note that even though the final solution variable here is called "Doping," that it is really the fixed and charged dopant ion that is used in semiconductor equations.

model

set small $1.0e-10
proc SetDoping {} {
   global small
   solution add name=Nd      solve const val = "1.1e15";#n-type base
   solution add name=Na      solve const val = "$small";#no p-type doping
   solution add name=Doping  solve const val = "((Nd)-(Na))"
   AddCharge 	Silicon	    "Doping"
}

warnings

This uses the procedure AddCharge to add the ionized (and therefore charged) dopant concentration to Poisson's equation.