3.2 Lattice and Thermal Properties

The semiconductor equations discussed in the previous section contain several important physical parameters. Accurate models for these parameters are crucial for successful device simulation. Lattice properties, such as the lattice constant, relative permittivity $\varepsilon_{\mathrm{r}}^{\mathrm{}}$, and mass density $\rho$ are already well determined for important semiconductors. Others, such as thermal conductivity and heat capacity, have been studied at room temperature. Due to the importance of these parameters for device simulation they are discussed in the following section. These are parameters of the Poisson equation (3.1) and the lattice heat flow equation (3.14), which are solved not only in the semiconductor, but also in the insulating materials. Therefore, models for important insulating materials, such as SiO$_2$ and Si$_3$N$_4$, are also presented.