AlGaAs/GaAs HEMT Id-Vgs and Id-Vds Characterization

hemtex03.in : AlGaAs/GaAs HEMT Id-Vgs and Id-Vds Characterization

Requires: Blaze
Minimum Versions: Atlas 5.22.1.R

This example demonstrates Id-Vds and Id-Vgs calculations in a single quantum-well AlGaAs/GaAs HEMT. It shows:

  • Construction of the heterojunction structure using Atlas syntax
  • Material and models parameter specification
  • Simulation of Id/Vds and Id/Vgs characteristics
  • Display of the results in TonyPlot

The device under consideration is the same as in the previous example in this section. The device geometry, mesh, regions, electrodes and doping distribution are described with the same sequence of statements as in the example above. The same material parameters and physical models are applied except for the impact ionization-generation model. Since the breakdown analysis is not the goal of this example and the range of voltages applied are far away from the breakdown region where the impact ionization effects become essential, the impact statement is excluded and no impact ionization-generation considered. The contact and interface statements are a repeat of those from the previous example.

After the initial solution is obtained, the gate voltage is set to 0, the structure under zero bias is displayed using TonyPlot, and the Id-Vds characteristic is calculated. As in the previous example the drain voltage is first ramped up to 0.3V. The solutions are obtained using the combined Gummel-Newton algorithm specified in the method gummel newton statement. The algorithm implies that if the solution does not converge in the course of Gummel iterations, the program will automatically switch over to the Newton algorithm.

Next the drain voltage is ramped up to 3V. This part of simulation is performed using the Newton method: method newton The results of simulation are saved in the log file and displayed using TonyPlot.

Simulation of the Id-Vgs characteristic is performed next. At the first stage the solution for Vgs=-0.9V and Vds=0.5V is obtained. Next, the gate voltage is ramped up to 0.6V with the step of 0.1V.

The results of simulation are again saved in a separate log file and displayed using TonyPlot.

To load and run this example, select the Load example button in DeckBuild. This will copy the input file and any support files to your current working directory. Select the run button to execute the example.