Abstract: A semiconductor device and a radio frequency circuit which are appropriate for multiband, multimode performance can be realized as a semiconductor device including a field-effect transistor formed on a semiconductor substrate, and include: ohmic electrodes serving as source and drain electrodes of the field-effect transistor, first and second Schottky electrodes provided between the ohmic electrodes and serving as gate electrodes of the field-effect transistor, and a third Schottky electrode provided and grounded between the first and second Schottky electrodes.

Abstract: A semiconductor device which detects a power level of a radio-frequency signal includes: a switch FET including: a semiconductor layer; a source electrode and a drain electrode; a first gate electrode; a second gate electrode formed between the first gate electrode and the drain electrode and on the semiconductor layer, each of the first gate electrode and the second gate electrode being in Schottky contact with the semiconductor layer, and the source electrode receiving the radio-frequency signal; a resistor having one end electrically connected to the first gate electrode and an other end electrically connected to the drain electrode via a capacitor; and a power detection terminal electrically connected to a connecting point between the resistor and the capacitor.

Abstract: A semiconductor device and a radio frequency circuit which are appropriate for multiband, multimode performance can be realized as a semiconductor device including a field-effect transistor formed on a semiconductor substrate, and include: ohmic electrodes serving as source and drain electrodes of the field-effect transistor, first and second Schottky electrodes provided between the ohmic electrodes and serving as gate electrodes of the field-effect transistor, and a third Schottky electrode provided and grounded between the first and second Schottky electrodes.

Abstract: A semiconductor device includes a semiconductor substrate of a first conductive type, a collector layer formed on the semiconductor substrate and made of a first semiconductor being of the first conductive type and having a higher resistance than that of the semiconductor substrate, an intrinsic base region having a junction surface with the collector layer and made of a second semiconductor of a second conductive type, and an emitter region having a junction surface with the intrinsic base region and made of a third semiconductor of the first conductive type. A periphery of the intrinsic base region is surrounded by an insulating region extending from the collector layer to the semiconductor substrate.

Abstract: There is provided a bipolar transistor that enables a desirably enhanced high-frequency performance to be obtained when used as an oscillation amplifier of an oscillation circuit, and that is miniaturized and reduced in cost. A capacitance adjustment line (11) connected to a base pad (7) forms a parasitic capacitor with respect to an N+ collector substrate by interposing an insulating film (3) and an N collector substrate therebetween, thereby increasing collector-base capacitance Ccb. This capacitor is incorporated into a bipolar transistor, which functions as an oscillation amplifier and has a small transistor operation region (2), at least as a part of a balance capacitor constituting the oscillation circuit in the course of production of a semiconductor.

Abstract: There is provided a bipolar transistor that enables a desirably enhanced high-frequency performance to be obtained when used as an oscillation amplifier of an oscillation circuit, and that is miniaturized and reduced in cost. A capacitance adjustment line (11) connected to a base pad (7) forms a parasitic capacitor with respect to an N+ collector substrate by interposing an insulating film (3) and an N collector substrate therebetween, thereby increasing collector-base capacitance Ccb. This capacitor is incorporated into a bipolar transistor, which functions as an oscillation amplifier and has a small transistor operation region (2), at least as a part of a balance capacitor constituting the oscillation circuit in the course of production of a semiconductor.

Abstract: There is provided a bipolar transistor that enables a desirably enhanced high-frequency performance to be obtained when used as an oscillation amplifier of an oscillation circuit, and that is miniaturized and reduced in cost. A capacitance adjustment line (11) connected to a base pad (7) forms a parasitic capacitor with respect to an N+ collector substrate by interposing an insulating film (3) and an N collector substrate therebetween, thereby increasing collector-base capacitance Ccb. This capacitor is incorporated into a bipolar transistor, which functions as an oscillation amplifier and has a small transistor operation region (2), at least as a part of a balance capacitor constituting the oscillation circuit in the course of production of a semiconductor.

Abstract: A semiconductor device includes a semiconductor substrate of a first conductive type, a collector layer formed on the semiconductor substrate and made of a first semiconductor being of the first conductive type and having a higher resistance than that of the semiconductor substrate, an intrinsic base region having a junction surface with the collector layer and made of a second semiconductor of a second conductive type, and an emitter region having a junction surface with the intrinsic base region and made of a third semiconductor of the first conductive type. A periphery of the intrinsic base region is surrounded by an insulating region extending from the collector layer to the semiconductor substrate.

Abstract: A bipolar transistor includes the first group of transistors 610a, the second group of transistors 610b, the third group of transistors 610c and the fourth group of transistors 610d. The groups of transistors have unit transistors with emitters, bases and collectors that are connected electrically in parallel and the number of unit transistors is different from group to group and 2, 4, 8, and 16, respectively.

Abstract: A bipolar transistor includes the first group of transistors 610a, the second group of transistors 610b, the third group of transistors 610c and the fourth group of transistors 610d. The groups of transistors have unit transistors with emitters, bases and collectors that are connected electrically in parallel and the number of unit transistors is different from group to group and 2, 4, 8, and 16, respectively.

Abstract: There is provided a bipolar transistor that enables a desirably enhanced high-frequency performance to be obtained when used as an oscillation amplifier of an oscillation circuit, and that is miniaturized and reduced in cost. A capacitance adjustment line (11) connected to a base pad (7) forms a parasitic capacitor with respect to an N+ collector substrate by interposing an insulating film (3) and an N collector substrate therebetween, thereby increasing collector-base capacitance Ccb. This capacitor is incorporated into a bipolar transistor, which functions as an oscillation amplifier and has a small transistor operation region (2), at least as a part of a balance capacitor constituting the oscillation circuit in the course of production of a semiconductor.