Patent ID: 7701032

Claim:
A compound semiconductor device comprising: a compound semiconductor substrate comprising a top surface portion; a transistor formed on the substrate and receiving a signal in a GHz frequency range, a drain and a source of the transistor being formed in the top surface portion of the substrate; a first direct current terminal connected with the transistor and applying a direct current to the transistor; a device element formed in or on the substrate adjacent the transistor; an isolation region disposed between the device element and the transistor; a separation element that is conductive and disposed on or in a top surface portion of the isolation region; a high resistance element formed on the substrate, the separation element being connected with a pad for a second direct current terminal through the high resistance element, the high resistance element being only a portion of a wiring connection between the pad and the separation element and comprising a portion of the semiconductor substrate that has a resistance higher than the rest of the wiring connection; and wherein the isolation region is part of the top surface portion of the substrate in which the drain and the source are formed.