Self-consistent electro-thermal simulations of AlGaN/GaN diodes by means of Monte Carlo method

Abstract

In this contribution we present the results from the simulation of an AlGaN/GaN heterostructure diode by means of a Monte Carlo tool where thermal effects have been included. Two techniques are investigated: (i) a thermal resistance method (TRM), and (ii) an advanced electro-thermal model (ETM) including the solution of the steady-state heat diffusion equation. Initially, a systematic study at constant temperature is performed in order to calibrate the electronic model. Once this task is performed, the electro-thermal methods are coupled with the Monte Carlo electronic simulations. For the TRM, several values of thermal resistances are employed, and for the ETM method, the dependence on the thermal-conductivity, thickness and die length is analyzed. It is found that the TRM with well-calibrated values of thermal resistances provides a similar behavior to ETM simulations under the hypothesis of constant thermal conductivity. Our results are validated with experimental measurements finding the best agreement when the ETM is used with a temperature-dependent thermal conductivity.

Impact of substrate and thermal boundary resistance on the performance of AlGaN/GaN HEMTs analyzed by means of electro-thermal Monte Carlo simulations

“…This is due to the shift of the V GS to higher values in SiC, leading to higher dissipated power. We have found that T av is linear with respect to the dissipated power, so that we can extract the slope of this linear fitting and define an equivalent thermal resistance R th as shown in [16]. In figure 4(a) 4(a)) we obtain the same transfer characteristics and transconductance as those provided by the HDEM, as can be seen by the solid lines of figures 2(a) and (b).…”

“…The simulation method used in this paper (heat diffusion equation model, HDEM) iteratively couples the MC electronic transport with the solution of the steady-state heat-diffusion equation (HDE) [16] (where radiation and convection losses are neglected): where T(r) and G(r) are the temperature and the dissipated power density, respectively, at position r, and k(r, T) is the temperature-dependent and inhomogeneous thermal conductivity. The thermal domain (region where the HDEM is applied), covers the whole device and is delimited by green dashed lines in figure 1.…”

High-frequency response and thermal effects in GaN diodes and transistors: modeling and experimental characterization

“…AlN 170 We perform the simulations with the heat-sink 8 at a temperature T = 300 K and the thermal conductivities of Table 3.3. In [36] it was argued that both models, TRM and ETM, are equivalent because the current is determined by the average temperature (T av ) inside the device, which is very similar with both models. Note that in the TRM the temperature is uniform, but in the ETM it changes from mesh to mesh.…”

“…There are both commercial and home-made simulators that can deal with thermal eects. Dierent models have been suggested like the thermal resistance approach [36], the solution of the steady-state heat conduction equation self-consistently with the microscopic transport in the device [37,38], or models based on analytical formulations [39,40].…”

“…In subsection 1.2.2, we described the techniques to include thermal eects. Two models were presented: the thermal resistance model (TRM) and the electrothermal model (ETM) [36]. In the TRM, all the meshes in the electrical domain have the same uniform temperature, given by Equation 3.13.…”