Contribution à l’étude des propriétés thermiques des composants à effet de champs MESFET GaAs.

Abstract

For the conception and the simulation of the microwave integrated circuits, it’s important to make up a sample theoretical model that takes into account all the effects which happen at the main constituting element of these circuits, which is the MESFET GaAs. This memory treats the simulation of the MESFET GaAs.that taken place in the first part, an analytical study of the static characteristics of the component based on the approximation of the gradual depletion area devoid of free charges .with a homogeneously doped channel, by holding account the influence of geometrical dimensions, thus the effect of mobility and the parasitic elements. the effect of the temperature in the behavior of the transistor MESFET GaAs. Then the influence of the temperature on the behavior of MESFET GaAs. Taking into consideration the difference between the temperature of the component and the ambient temperature by electrical analogy, the thermal resistance RTH is determined as the ratio of the temperature deviation to the heat dissipation. Note that the heating is generated a distance smaller than the gate length of the drain side and there is almost no power dissipation under the source and drain contacts. The results obtained make it possible to determine the properties of the current under the effect of the optimal geometrical and physical parameters of the component with a view to a microwave power amplification application.A compromise is given between the various parameters as well as the choice of a law of mobility valid for gallium arsenide. These results allow the development of geometries of the component adapted of the specific uses, and will play a key role in the field of the CAO of microwave circuits.