Abstract: A semiconductor device includes a semiconductor layer stack formed on a substrate, a first ohmic electrode and a second ohmic electrode which are formed on the semiconductor layer stack, and are spaced from each other, a first control layer formed between the first ohmic electrode and the second ohmic electrode, and a first gate electrode formed on the first control layer. The first control layer includes a lower layer, an intermediate layer which is formed on the lower layer, and has lower impurity concentration than the lower layer, and an upper layer which is formed on the intermediate layer, and has higher impurity concentration than the intermediate layer.

Abstract: A bidirectional switching device includes a semiconductor multilayer structure made of a nitride semiconductor, a first ohmic electrode and a second ohmic electrode which are formed on the semiconductor multilayer structure, and a first gate electrode and a second gate electrode. The first gate electrode is covered with a first shield electrode having a potential substantially equal to that of the first ohmic electrode. The second gate electrode is covered with the second shield electrode having a potential substantially equal to that of the second ohmic electrode. An end of the first shield electrode is positioned between the first gate electrode and the second gate electrode, and an end of the second shield electrode is positioned between the second gate electrode and the first gate electrode.

Abstract: A bidirectional switch includes a plurality of unit cells 11 including a first ohmic electrode 15, a first gate electrode 17, a second gate electrode 18, and a second ohmic electrode 16. The first gate electrodes 15 are electrically connected via a first interconnection 31 to a first gate electrode pad 43. The second gate electrodes 18 are electrically connected via a second interconnection 32 to a second gate electrode pad 44. A unit cell 11 including a first gate electrode 17 having the shortest interconnect distance from the first gate electrode pad 43 includes a second gate electrode 18 having the shortest interconnect distance from the second gate electrode pad 44.

Abstract: A motor driving circuit includes a three-phase inverter circuit 8, including three upper-arm switching elements 56a to 56c for driving upper arms of different phases of a three-phase motor 3, and three lower-arm switching elements 56d to 56f for driving lower arms of different phases. At least one of the upper-arm switching elements 56a to 56c and the lower-arm switching elements 56d to 56f is a semiconductor element that performs a diode operation. The diode operation is an operation in which a voltage less than or equal to a threshold voltage of a gate electrode G is applied to the gate electrode G with reference to a potential of a first ohmic electrode S, thereby conducting a current flow from the first ohmic electrode S to a second ohmic electrode D and blocking a current flow from the second ohmic electrode D to the first ohmic electrode S.

Abstract: A bidirectional switch includes a semiconductor element and a substrate potential stabilizer. The semiconductor element includes a first ohmic electrode and a second ohmic electrode, and a first gate electrode and a second gate electrode, which are sequentially formed on the first ohmic electrode between the first ohmic electrode and the second ohmic electrode. The substrate potential stabilizer sets a potential of the substrate lower than higher one of a potential of the first ohmic electrode or a potential of the second ohmic electrode.

Abstract: A power converter includes an input terminal configured to be connected to a power supply, an output terminal, and a first switching element coupled between the input terminal and the output terminal. The first switching element includes a semiconductor multilayer structure formed on a substrate and made of a nitride semiconductor, a gate electrode formed on the semiconductor multilayer structure, a first and a second ohmic electrode, and a back electrode formed on a back surface of the substrate. A potential is supplied from the power supply connected to the input terminal to the back electrode so that a potential difference between the back surface and the second ohmic electrode is reduced. When the first switching element is in the on-state, a positive voltage bias is applied to the back electrode.

Abstract: An electronic equipment includes a cooling system using boiling and condensation of a refrigerant, especially stabilizes the cooling performance, and reduces the influence which vibration accompanying phase change of boiling and condensation gives to the electronic equipment. Electronic equipment includes a cooling system including a cooling part which cools heat generating from a heat generator such as a heat generating component by using boiling of a refrigerant and is thermally connected to the heat generator such as the heat generating element, a heat radiation part which radiates heat absorbed by the refrigerant in the cooling part by condensation, a refrigerant drive part for delivering the condensed refrigerant to the cooling part again, and piping which fluidly connects them, and the electronic equipment includes preliminary heating means for heating the refrigerant, which flows to the cooling part from the refrigerant drive part, between the refrigerant drive part and the cooling part.

Abstract: A semiconductor device includes a semiconductor layer stack 13 formed on a substrate 11 and having a channel region, a first electrode 16A and a second electrode 16B formed spaced apart from each other on the semiconductor layer stack 13, a first gate electrode 18A formed between the first electrode 16A and the second electrode 16B, and a second gate electrode 18B formed between the first gate electrode 18A and the second electrode 16B. A first control layer 19A having a p-type conductivity is formed between the semiconductor layer stack 13 and the first gate electrode 18A.

Abstract: A power converter includes an input terminal configured to be connected to a power supply, an output terminal, and a first switching element coupled between the input terminal and the output terminal. The first switching element includes a semiconductor multilayer structure formed on a substrate and made of a nitride semiconductor, a gate electrode formed on the semiconductor multilayer structure, a first and a second ohmic electrode, and a back electrode formed on a back surface of the substrate. A potential is supplied from the power supply connected to the input terminal to the back electrode so that a potential difference between the back surface and the second ohmic electrode is reduced. When the first switching element is in the on-state, a positive voltage bias is applied to the back electrode.

Abstract: A power conversion circuit includes a bidirectional switch 2. The bidirectional switch 2 has a first gate terminal G1, a second gate terminal G2, a first ohmic terminal S1 and a second ohmic terminal S2. The bidirectional switch 2 has four operation states. In the first state, the bidirectional switch 2 operates as a diode having a cathode as the first ohmic terminal S1 and an anode as the second ohmic terminal S2. In a second state, the bidirectional switch 2 operates as a diode having an anode as the first ohmic terminal S1 and a cathode as the second ohmic terminal S2. In a third state, the bidirectional switch 2 is bidirectionally conductive with via a diode between the first and second ohmic terminals S1 and S2. In a fourth state, the bidirectional switch 2 cuts off a bidirectional current between the first and second ohmic terminals.

Abstract: A semiconductor device includes: a semiconductor chip; a protective film and an insulating film sequentially stacked over the semiconductor chip, and each having openings that expose source, drain, and gate pads; a heat dissipation terminal made of a material having a higher thermal conductivity than the insulating film; connection terminals formed on the source, drain, and gate pads and surrounded by the insulating film; and a mount substrate having connection pads. The semiconductor chip has a source electrode having a plurality of source fingers, a drain electrode having a plurality of drain fingers, and a gate electrode having a plurality of gate fingers. The source, drain, and gate pads are connected to the source electrode, the drain electrode, and the gate electrode, respectively. The connection terminals are respectively connected to the connection pads. The heat dissipation terminal is in close contact with the mount substrate.

Abstract: A semiconductor device includes a semiconductor layer stack formed on a substrate, a first ohmic electrode and a second ohmic electrode which are formed on the semiconductor layer stack, and are spaced from each other, a first control layer formed between the first ohmic electrode and the second ohmic electrode, and a first gate electrode formed on the first control layer. The first control layer includes a lower layer, an intermediate layer which is formed on the lower layer, and has lower impurity concentration than the lower layer, and an upper layer which is formed on the intermediate layer, and has higher impurity concentration than the intermediate layer.

Abstract: A material of a gate electrode is a conductive oxide having a higher work function than that of conventionally used Pd and so on, thereby achieving a normally-off transistor without reducing the sheet carrier concentration of a heterojunction. It is thus possible to achieve a normally-off operation while reducing an increase in the specific on-state resistance.

Abstract: A nitride semiconductor device includes a semiconductor stacked structure which is formed of a nitride semiconductor having a first principal surface and a second principal surface opposed to the first principal surface and which includes an active layer. The first principal surface of the semiconductor stacked structure is formed with a plurality of indentations whose plane orientations are the {0001} plane, and the plane orientation of the second principal surface is the {1-101} plane. The active layer is formed along the {1-101} plane.

Abstract: A material of a gate electrode is a conductive oxide having a higher work function than that of conventionally used Pd and so on, thereby achieving a normally-off transistor without reducing the sheet carrier concentration of a heterojunction. It is thus possible to achieve a normally-off operation while reducing an increase in the specific on-state resistance.

Abstract: A plasma display panel driving device includes an electrode driving unit for generating a drive pulse to be applied to an electrode of a plasma display panel. The electrode driving unit has a plurality of switches. At least one of the plurality of switches is a switch device including a dual-gate semiconductor device. The dual-gate semiconductor device 10 has a semiconductor multilayer 13 formed on a substrate 11 and made of a nitride semiconductor or a silicon carbide semiconductor, a source electrode 16 and a drain electrode 17 formed and spaced apart from each other on the semiconductor multilayer 13, and a first gate electrode 18A and a second gate electrode 18B formed between the source electrode 16 and the drain electrode 17, successively from the source electrode 16 side.

Abstract: A material of a gate electrode is a conductive oxide having a higher work function than that of conventionally used Pd and so on, thereby achieving a normally-off transistor without reducing the sheet carrier concentration of a heterojunction. It is thus possible to achieve a normally-off operation while reducing an increase in the specific on-state resistance.

Abstract: A bidirectional switch includes a plurality of unit cells 11 including a first ohmic electrode 15, a first gate electrode 17, a second gate electrode 18, and a second ohmic electrode 16. The first gate electrodes 15 are electrically connected via a first interconnection 31 to a first gate electrode pad 43. The second gate electrodes 18 are electrically connected via a second interconnection 32 to a second gate electrode pad 44. A unit cell 11 including a first gate electrode 17 having the shortest interconnect distance from the first gate electrode pad 43 includes a second gate electrode 18 having the shortest interconnect distance from the second gate electrode pad 44.

Abstract: A field effect transistor includes a first nitride semiconductor layer 13 and a second nitride semiconductor layer 14 having a band gap larger than that of the first nitride semiconductor layer 13 which are formed in this order in an upward direction on a conductive substrate 11, a source electrode 15 and a drain electrode 16 which are electrically connected to a two-dimensional electron gas layer 21, and a gate electrode 18. A rise voltage of a drain-substrate current is lower than a rise voltage of a drain-gate current and a rise voltage of a drain-source current.