D.3 Oxide Traps

Trapped charge in insulator segments can be simulated using the model oxideTrap which must be specified in the Phys section of the input deck. In the following example the oxide trap model is evaluated in the segment GateOxide for a concentration of negative traps of $\ensuremath{N_\mathrm{T}}=1e19 cm-3$ at an energy level of 2eV below the conduction band edge in the dielectric and an occupancy of 0.1%. The model keywords are summarized in Table D.6.

  Phys 
  { 
     +GateOxide
     {
        oxideTrap = "Pure";
        OxideTrap
        {
           Pure
           {
              Nt        = 1e19 "cm^-3";  // trap concentration
              type      = "negative";    // charge state
              occupancy = 0.001;         // trap occupancy
              energy    = 2 "eV";        // trap energy level
           }
        }
     }
     +Gate
     {
        Contact { Ohmic { Ew = -0.5 eV; }} 
     }       
  }

A charge state of $-1$ ("negative"), 0 ("neutral"), and $+1$ ("positive") can be chosen. The trap charge is self-consistently considered in the POISSON equation. The possible keyword values are shown in Table D.7.

Table D.6: OxideTrap model keywords.

Symbol	Keyword	Type	Unit
$\ensuremath{N_\mathrm{T}}$	Nt	Quantity	cm$^{-3}$
$\ensuremath{f_\mathrm{T}}$	occupancy	Real
$\ensuremath{{\mathcal{E}}_\mathrm{T}}$	energy	Quantity	eV

Table D.7: OxideTrap model trap charge state.

Keyword	Type	Values
type	String	"negative", "neutral", "positive"

A. Gehring: Simulation of Tunneling in Semiconductor Devices