Improved fabrication technologies for GaAs power MMICs

Describes the technology enhancements necessary to produce GaAs IC chips that combine small signal and power functions on a single chip. The well established small signal production MMIC process has a final substrate thickness of 200 μm and the active layers are prepared by ion implantation into semi-insulating GaAs substrates, both these aspects must be retained when fabricating power MMICs in order to maintain a high yield commercially compatible process. The realisation of power MMIC structures under these two main constraints has required the development of a new material doping specification and a novel heatsink structure