The Boundary Conditions for Field Simulations in Insulators

Inhalt:
Simulations of DC electric field distributions in insulators must take into account space charges, which can induce significant field distortions. Their behavior is strongly governed by the physics at electrode contacts and surfaces or interfaces. For different contact types, we discuss boundary conditions to the carrier densities, and illustrate consequences for the electric behavior with examples for unipolar transport. In particular, it is shown that only the generic boundary conditions are able to reproduce the full transient crossover from capacitive to space charge limited field distribution. Additionally, the space charge limited field distribution at an insulator-insulator interface is briefly investigated.