Invited paper Avalanche diode oscillators III. Design and analysis : the future

This is the final part of this series of papers. In it we develop more intricate versions of the ‘ avalanche plus drift ’ combinations, We examine the double-drift structure, the possibility of a double avalanche structure and outline the properties of a heterojunction device. We continue to discuss possible different materials, including more unusual semiconductors. The remainder of the main part of this paper is devoted to a critical account of the various modelling techniques which may be used to give a theoretical account of the behaviour of the device. In the paper so far, we have used the simplest possible models : these do, of course, have some limitations, and we describe some of these. The potentially most accurate models involve some form of computer simulation. An outline of our present approach to the simulation problem is given, along with a description of some of the pitfalls which the user of this technique may encounter. Finally, three appendices fill in some of the more important omissions which did not fall into the main text. Initially we consider the derivation of some of the often quoted small signal parameters, and some interpretation of their relevance to large signal situations. The second appendix is devoted to a diffusion-inclusive description of the avalanche zone properties, and finally, n simple model for the description of high efficiency structures is described.