Abstract: A substrate carrier for a ceramic substrate which supports one or more high power semiconductor devices which is fabricated from a metal base composite and which includes strategically located high conductivity copper based inserts to provide an effective heat transfer path to a heat sink for high power electronic devices. The coefficient of thermal expansion of both the metal based composite and the copper based inserts substantially match that of the substrate. The substrate carrier is formed by a pressure casting process where a porous preform of SiC, for example, is infiltrated with molten aluminum.

Abstract: A package for relatively high power transistors including heat conducting mounting flange having a relatively large "footprint" relative to the area covered by at least one active chip supported thereby and comprised of a plurality of bipolar silicon-carbide transistors. The transistors are located on a dielectric substrate brazed to the flange. A plurality of screw mounting holes, preferably eight in number, are included in the mounting flange adjacent the outer edge of the dielectric substrate so as to surround the chip. Mounting screws in the eight mounting holes together with a relatively large flange/ground plane interface significantly improves heat dissipation for the heat generated by the silicon carbide transistors by promoting radial heat spreading through the heat conductive metal flange.

Abstract: A metallic heatsink consisting of material having high thermal conductivity includes plural regions of finstock which underlie a ceramic window type frame enclosing at least one heat spreading insulator member on which is located at least one silicon carbide semiconductor chip including a plurality of silicon carbide transistors. On both sides of the chip are impedance transformation elements connecting bondwires to input and output leads extending through the ceramic window frame for connection of the chip to external circuitry.