| 摘要 |
PURPOSE:To obtain a microwave monolithic IC, which has structure in which thermal resistance is reduced and circuit loss thereof is small, by removing the back of a GaAs substrate opposite to a FET section as a heat-generating section to a trapezoid shape. CONSTITUTION:An active layer 2 for a FET is formed on a semi-insulating GaAs substrate 1. A gate 3 and a drain 4 for the FET are connected to matching circuits 5, and connected to external circuits from bonding pads 6. A source 7 is connected to a grounding electrode 9 by a via hole 8. The back of the substrate 1 takes a trapezoid, and is removed so as not to reach to the layer 2. A microwave monolithic IC type power amplifier having such structure is assembled on a metal, and thermal resistance is reduced because the hole 8 is clogged by a solder material. Loss is also small because the thickness of the substrate in the matching circuit is thick. Since the line of the circuit 5 is formed to a tapered shape 12, the impedance of the circuit 5 is kept constant, and the matching properties of the circuit 5 is not damaged. |
