A widely used method for numerical discretization is the method of Box Integration, also known as Finite Boxes, Finite Volumina method for three dimensions, or Finite Areas for two dimensions. The applicability of this methodology is closely coupled to Delaunay grids, described before [35].
In the field of electrical device simulation, several differential equations are applied. The first group is derived by stationary electric field calculations as a result of applying the Maxwell equations. A similar differential equation type is obtained by observing diffusion or thermal conductance processes, with the difference of an additional time dependent term. These types of differential equations are described first. The second class results from the semiconductor equations, in its simplest form the drift-diffusion model. This type will be described later.
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