Comprehensive models for the analysis of high-efficiency GaAs IMPATT's

High-efficiency GaAs IMPATT's have several distinctive characteristics which have been the subject of considerable theoretical investigation. In general, the approach has been to isolate a particular physical mechanism and consider its effect on the device. In this paper, the interaction between all these effects is discussed in terms of comprehensive models. Accurate numerical results are derived from a full computer simulation of the device. These results provide a number of new insights into device operation, especially the importance of thermal effects. An overall assessment of the numerical results leads to the development of a graphical construction which incorporates the most important physical effects in one simple diagram. This enables a rapid and accurate estimate of the effects of structure, temperature, current density, operating frequency, and RF voltage on the operation of the device. Finally, the models described are used to derive a design procedure for a high-efficiency structure.