The development of a foundry compatible power MMIC production technology

The technology developed to provide a medium-power enhancement to Plessey´s GaAs foundry MMIC (monolithic microwave IC) process and design capability is described. These process improvements have been in two major areas, namely, the identification and optimization of an ion implantation routine for power MESFET devices, and the development of a suitable heatsink technology compatible with the standard foundry IC process. Novel integral heatsink structures are developed which involve fabricating ´bathtub-shaped´ heatsinks under the FET. A range of power FET devices fabricated using ion implanted material incorporating a p/sup -/ compensating layer are characterized. The devices have shown excellent performance in terms of gain, peripheral power density, and power added efficiency. These devices dissipate 20 watts of heat through the integral heatsink, thus clearly demonstrating the effectiveness of the new heatsink technology. A method for fabricating power GaAs MMICs on a substrate of manageable thickness has thus been demonstrated.<>