Patent ID: 7391067

Claim:
An amplifier, said amplifier comprising: a Si heat spreader substrate having a thickness of about one mil (25 micrometers (μm)), and defining first and second surfaces, said first surface supporting a layer of one of AlGaN and GaN semiconductor materials, the layer of semiconductor material defining a planar active transistor arrangement including drain, gate, and source portions, and also defining conductors for interconnecting said drain and gate portions, and through vias extending from said second surface of said heat spreader to said source portions; a layer of gold extending over said second surface of said heat spreader and into said through vias to make thermal and electrical contact with said source portions, said layer of gold having a thickness of about 10 to 20 micrometers (μm); a planar matching circuit including circuit nodes, some of which require ground connections, and also including at least connecting pads which, when said matching circuit is juxtaposed with said active transistor arrangement, are registered with one of (a) the drain conductors and (b) the gate conductors of said active transistor arrangement, said planar matching circuit being defined on a first surface of a GaAs substrate having a thickness of about 4 mils (100 micrometers (μm)), said GaAs substrate defining through vias extending from a second surface to those of said circuit nodes requiring ground connection, said GaAs substrate further having a layer of gold extending over said second surface and into said through vias to make contact with said circuit nodes; a stepped heat sink defining first and second mutually parallel planar surfaces, said layer of gold of said heat spreader being affixed to said first planar surface of said stepped heat sink, and said layer of gold of said GaAs substrate being affixed to said second planar surface of said stepped heat sink, the distance between the planes of said first and second planar surfaces of said heat sink being equal to the difference between the thickness of said GaAs substrate and the sum of the thicknesses of said heat spreader and said layer of gold; and bond wire electrical interconnections extending between said connecting pads of said matching circuit and conductors of said active transistor arrangement.