Abstract: A semiconductor device is preferably excellent in characteristics such as a loss characteristic. Provided is a semiconductor device including a semiconductor substrate, including an upper-surface electrode provided on an upper surface of the semiconductor substrate; an lower-surface electrode provided on a lower surface of the semiconductor substrate; a transistor portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; a first diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; and a second diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode, wherein the first diode portion and the second diode portion have different resistivities in a depth direction of the semiconductor substrate.

Abstract: A semiconductor device is preferably excellent in characteristics such as a loss characteristic. Provided is a semiconductor device including a semiconductor substrate, including an upper-surface electrode provided on an upper surface of the semiconductor substrate; an lower-surface electrode provided on a lower surface of the semiconductor substrate; a transistor portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; a first diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; and a second diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode, wherein the first diode portion and the second diode portion have different resistivities in a depth direction of the semiconductor substrate.

Abstract: A semiconductor device is preferably excellent in characteristics such as a loss characteristic. Provided is a semiconductor device including a semiconductor substrate, including an upper-surface electrode provided on an upper surface of the semiconductor substrate; an lower-surface electrode provided on a lower surface of the semiconductor substrate; a transistor portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; a first diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode; and a second diode portion provided in the semiconductor substrate and connected to the upper-surface electrode and the lower-surface electrode, wherein the first diode portion and the second diode portion have different resistivities in a depth direction of the semiconductor substrate.

Abstract: A power semiconductor module has a circuit assembly body, which includes a metal base, a ceramic substrate, and a power semiconductor chip, and is combined with a package having terminals formed integrally. The ceramic substrate of the module has a structure such that an upper circuit plate and a lower plate are joined to both sides of a ceramic plate, respectively, and the metal base and the ceramic substrate are fixed to one another using solder, thereby improving reliability and lengthening a life of a power semiconductor module by optimizing a ceramic substrate and a metal base thereof, the dimensions thereof, and material and method used for a join formed between the ceramic substrate and metal base.

Abstract: A power semiconductor module has a circuit assembly body, which includes a metal base, a ceramic substrate, and a power semiconductor chip, and is combined with a package having terminals formed integrally. The ceramic substrate of the module has a structure such that an upper circuit plate and a lower plate are joined to both sides of a ceramic plate, respectively, and the metal base and the ceramic substrate are fixed to one another using solder, thereby improving reliability and lengthening a life of a power semiconductor module by optimizing a ceramic substrate and a metal base thereof, the dimensions thereof, and material and method used for a join formed between the ceramic substrate and metal base.

Abstract: A power semiconductor module has a circuit assembly body, which includes a metal base, a ceramic substrate, and a power semiconductor chip, and is combined with a package having terminals formed integrally. The ceramic substrate of the module has a structure such that an upper circuit plate and a lower plate are joined to both sides of a ceramic plate, respectively, and the metal base and the ceramic substrate are fixed to one another using solder, thereby improving reliability and lengthening a life of a power semiconductor module by optimizing a ceramic substrate and a metal base thereof, the dimensions thereof, and material and method used for a join formed between the ceramic substrate and metal base.

Abstract: A semiconductor device can be formed with fewer voids in the solder bonding a laminate of a silicon chip, an insulator substrate, and a metal base, with a solder layer positioned between the layers. After placing the laminate in a furnace, it is evacuated and then pressurized with hydrogen gas, and then heated to melt the solder. While maintaining the heat, the furnace is again evacuated to remove voids in the solder, and then the furnace is positively pressurized again with hydrogen gas to prevent holes produced by the voids traveling in the solder, and to obtain a uniform solder fillet shape. Thereafter the laminate is rapidly cooled to obtain a finer grain solder to increase the rate of creep to quickly remove the warping of the laminate to the original state.

Abstract: A power semiconductor module has a circuit assembly body, which includes a metal base, a ceramic substrate, and a power semiconductor chip, and is combined with a package having terminals formed integrally. The ceramic substrate of the module has a structure such that an upper circuit plate and a lower plate are joined to both sides of a ceramic plate, respectively, and the metal base and the ceramic substrate are fixed to one another using solder, thereby improving reliability and lengthening a life of a power semiconductor module by optimizing a ceramic substrate and a metal base thereof, the dimensions thereof, and material and method used for a join formed between the ceramic substrate and metal base.

Abstract: A power semiconductor module has a circuit assembly body, which includes a metal base, a ceramic substrate, and a power semiconductor chip, and is combined with a package having terminals formed integrally. The ceramic substrate of the module has a structure such that an upper circuit plate and a lower plate are joined to both sides of a ceramic plate, respectively, and the metal base and the ceramic substrate are fixed to one another using solder, thereby improving reliability and lengthening a life of a power semiconductor module by optimizing a ceramic substrate and a metal base thereof, the dimensions thereof, and material and method used for a join formed between the ceramic substrate and metal base.

Abstract: A semiconductor device can be formed with fewer voids in the solder bonding a laminate of a silicon chip, an insulator substrate, and a metal base, with a solder layer positioned between the layers. After placing the laminate in a furnace, it is evacuated and then pressurized with hydrogen gas, and then heated to melt the solder. While maintaining the heat, the furnace is again evacuated to remove voids in the solder, and then the furnace is positively pressurized again with hydrogen gas to prevent holes produced by the voids traveling in the solder, and to obtain a uniform solder fillet shape. Thereafter the laminate is rapidly cooled to obtain a finer grain solder to increase the rate of creep to quickly remove the warping of the laminate to the original state.

Abstract: A power semiconductor module has a circuit assembly body, which includes a metal base, a ceramic substrate, and a power semiconductor chip, and is combined with a package having terminals formed integrally. The ceramic substrate of the module has a structure such that an upper circuit plate and a lower plate are joined to both sides of a ceramic plate, respectively, and the metal base and the ceramic substrate are fixed to one another using solder, thereby improving reliability and lengthening a life of a power semiconductor module by optimizing a ceramic substrate and a metal base thereof, the dimensions thereof, and material and method used for a join formed between the ceramic substrate and metal base.

Abstract: A control device for controlling a double gate semiconductor device having a second gate electrode for controlling transition from a thyristor operation to a transistor operation, and a first gate electrode for controlling transition from transistor operation to an ON/OFF operation, and for controlling a current passing from a collector electrode to an emitter electrode, includes a first gate control circuit for delaying a turn-off signal to the double gate semiconductor device and applying the turn-off signal to the first gate electrode.

Abstract: A semiconductor device includes a main insulated gate type switching element having a gate electrode and controllable by a gate voltage applied to the gate electrode, a current detecting insulated gate type switching element connected in parallel to the main insulated gate type switching element, a detecting resistor for detecting a current flowing in the current detecting insulated gate type switching element, a gate controlling element capable of controlling the gate voltage by a drop voltage in the detecting resistor, and a gate control relieving element for relieving a varying speed of the gate voltage varied based on an operation of the gate controlling element.

Abstract: The disclosure concerns pyrimidine derivatives represented by the following general formulas [I] and [I'] and having antiviral activity, particularly antiretroviral activity such as anti-HIV activity: ##STR1## and pharmaceutical compositions having antiviral activity and comprising the above-described derivative(s) as an active ingredient.

Abstract: A semiconductor device thyristor structure includes a first conductive type collector region, second conductive type and first conductive type base regions, and a second conductive type emitter region. First conductive type regions and second conductive type regions have respective first and second type majority carriers. A first MOSFET injects the second type majority carriers into the second conductive type base region. A second MOSFET is opened and closed independent of the first MOSFET and extracts the first type majority carriers from the first conductive type base region. A third MOSFET has a first gate electrode which is also a gate electrode of the first MOSFET, for extracting the first type majority carriers from the first conductive type base region. First conductive type and second conductive type emitter regions are formed within the first conductive type base region and an emitter voltage can be simultaneously applied to these emitter regions.

Abstract: A snubber circuit, for absorbing voltage spikes applied to a power semiconductor device used as a switching means, utilizes the junction capacitance of a directly connected semiconductor device, thereby avoiding the need for a separate high-voltage capacitor. Embodiments shown use either a MOSFET or a bipolar transistor with a resistor connected in parallel between the gate (base) and the source (emitter) of the MOSFET (or bipolar transistor.) The snubber circuit of the present invention may also be a module integrally formed on a radiating base of the power semiconductor device.

Abstract: A pyrimidine nucleoside derivative and pharmaceutically acceptable salt thereof specified by the presence of ethyl group or isopropyl group at 5-position of the pyrimidine ring and the presence of a (substituted) phenylthio or a (substituted) benzyl group at 6-position of the pyrimidine ring is provided. The pyrimidine nucleoside derivative and pharmaceutically acceptable salt thereof show a markedly higher anti-retroviral activity than conventional analogous compounds and have a relatively low toxicity against the host cells, and therefore, are useful as an active ingredient of antiviral agent.

Abstract: In a reverse-bias control circuit for a voltage-driven switching element which turns on upon receiving a forward-bias voltage and turns off upon receiving a reverse-bias voltage, a step-down circuit is included which serves for stepping down a reverse-bias voltage after a time delay which is substantially equal to the turn-off delay of the voltage-driven switching element. The control circuit further includes a recovery circuit for stopping operation of the step-down circuit after a delay which is substantially equal to the total turn-off time of the voltage-driven switching element. The reverse-bias control circuit serves to reduce the reverse-bias voltage, thereby blocking surge-voltage disturbances, without increasing the turn-off delay time.

Abstract: 6-substitutted acyclopyrimidine nucleoside derivatives represented by the following general formula I: ##STR1## wherein R.sup.1 represents a hydrogen or halogen atom or a group of alkyl, alkenyl, alkynyl, alkylcarbonyl, arylcarbonyl, arylcarbonylalkyl, arylthio or aralkyl; R.sup.2 represents a group of arylthio, alkylthio, cycloalkylthio, aryl sulfoxide, alkyl sulfoxide, cycloalkyl sulfoxide, alkenyl, alkynyl, aralkyl, arylcarbonyl, arylcarbonylalkyl or aryloxy; R.sup.3 represents a hydroxyalkyl group of which alkyl portion may contain an oxygen atom; X represents an oxygen or sulfur atom or amino group; Y represents an oxygen or sulfur atom; and A represents .dbd.N-- or --NH-- or pharmaceutically acceptable salts thereof, processes for their preparation and antiviral agents containing them as active ingredients.

Abstract: The disclosure concerns pyrimidine derivatives represented by the following general formulas [I] and [I′] and having antiviral activity, particularly antiretroviral activity such as anti-HIV activity: and pharmaceutical compositions having antiviral activity and comprising the above-described derivative(s) as an active ingredient.