Abstract: The RF device of the present invention includes: a semiconductor substrate; and first and second semiconductor components provided on the substrate. Each of the components includes source electrodes, a gate electrode and a drain electrode. And multiple through holes, which pass through the substrate in the thickness direction, are opened in a region of the substrate between the two components. To enhance the effect of suppressing electrical interference between the components, a gap between two adjacent ones of the through holes is preferably smaller than the thickness of the substrate.

Abstract: A semiconductor device has the following structure: a lead frame 2 is disposed on the center of a package 1, signal terminal electrodes 3 through 7 are disposed on edges of the package, a semiconductor chip 8 is mounted on the lead frame 2, a grounding electrode 16 having a grounding potential is disposed between the signal terminal electrodes 4 and 5, and a grounding electrode having a grounding potential is disposed between the signal terminal electrodes 5 and 6. This structure increases an electrical separation between the signal terminal electrodes.

Abstract: A drain and a source of a field-effect transistor are connected to first and second signal terminals, respectively. A first control terminal is connected to a gate. A first resistor is interposed between the gate and the first control terminal. Capacitors are interposed between the source/drain and the first and second signal terminals, respectively. A control terminal is connected to at least one of the source/drain via a second resistor. High frequency signals supplied through the first signal terminal is sent through the field-effect transistor and outputted through the second signal terminal, and a quantity of the transmitted high frequency signals is controlled by a control voltage signal applied across the first and second control terminals. This structure provides a high frequency semiconductor integrated circuits which reduces a power consumption and an occupied area, increases a switchable power, suppresses output distortion, and simplifies a peripheral circuit.