New models for physical properties with respect to material composition and
strain conditions due to lattice mismatch have to be developed. The models must
be valid for the whole composition range in the temperature range between 70 K
and 500 K. Anisotropic effective carrier masses, density of states, and
carrier mobilities should be considered. A built-in feature for automatic
estimation of the strain condition based on empirical relation for the
growth-condition dependent critical layer thickness (see
e.g. [127,128]) can also be developed. The materials used in two
consecutive layers can be checked if they cannot be grown without a lattice
mismatch. It is imaginable to apply the algorithm for estimation of the strain
condition of arbitrary relevant material structures. The convergence behavior
must be optimized and the complexity of the models should be cross-checked with
the computational effort in order to ensure the effectiveness of the new
models.
Possible simulation applications in the future could be the simulation of leakage currents at low bias in GaAs-based HBTs, breakdown simulation in III-V devices, thermal investigations not only in the device, but also in the interconnects. The accuracy of the device simulation for all devices has to be verified not only against DC-, but also against RF-measurements. Simulations will aid reliability investigations also in the future, as they offer practical solutions.