Modelling
Modelling is a critical tool that helps us to understand the obtained experimental results. Modelling also helps with the design of next generation devices.
Thermal Modelling
We perform thermal modelling using finite element analysis and advanced phonon transport modelling. Thermal simulation is always supported with experimental data: temperature measurement in an actual device under operation, combined with thermal simulation allows us to determine thermal conductivities, thermal boundary resistances and thermal capacitances of materials used in the device. It can also help by predicting what effect a certain design has on channel temperature. All this can only be made possible with experimentally validated thermal simulations.
Figure 1. Molecular dynamics of heat transport on the atomic level in diamond
Figure 2. Temperature rise in GaN HEMT under DC vs RF operation
Electrical Simulation
Electrical simulation is performed using drift diffusion models. This allows input of layer structure, doping density, electronic transport as well as trap states (energy, density, capture cross sections), enabling the simulation of the current voltage characteristics of the devices. Comparing simulation to experimental data not only allows us to identify what is missing from the model and develop a deeper physical understanding of novel device operation, but also allows us to extract further information from the experimental data, including the detailed physical location of traps such as near-the-gate, in-source or drain-access regions, or the identification of parasitic leakage paths.
Figure 3. Drift diffusion electrical simulation of GaN power HEMT