Temperature Analysis and Thermal Resistance of a Matrix of Impatt Diodes

A composite Impatt device consisting of a matrix of Impatt diodes, in a multimesa structure, ture, with a common n + electrode region and a common heatsink, represents a complex non-linear thermal problem since each diode heat contribution depends indirectly on its junction temperature. Numerical analysis is used to obtain a temperature map of such a composite device and its thermal resistance as functions of the ratio of the distance between individual diodes in the array d and their diameter a. It is shown, for instance, that a 60% reduction in thermal resistance can be achieved for d/a = 5, compared to a single diode of the same total area. The same analysis can be used for any matrix of temperature dependent heat sources, in close proximity on a common heatsink.