Abstract: A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.

Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.

Abstract: Hydrogen atoms and crystal defects are introduced into an n? semiconductor substrate by proton implantation. The crystal defects are generated in the n? semiconductor substrate by electron beam irradiation before or after the proton implantation. Then, a heat treatment for generating donors is performed. The amount of crystal defects is appropriately controlled during the heat treatment for generating donors to increase a donor generation rate. In addition, when the heat treatment for generating donors ends, the crystal defects formed by the electron beam irradiation and the proton implantation are recovered and controlled to an appropriate amount of crystal defects. Therefore, for example, it is possible to improve a breakdown voltage and reduce a leakage current.

Abstract: Hydrogen atoms and crystal defects are introduced into an n? semiconductor substrate by proton implantation. The crystal defects are generated in the n? semiconductor substrate by electron beam irradiation before or after the proton implantation. Then, a heat treatment for generating donors is performed. The amount of crystal defects is appropriately controlled during the heat treatment for generating donors to increase a donor generation rate. In addition, when the heat treatment for generating donors ends, the crystal defects formed by the electron beam irradiation and the proton implantation are recovered and controlled to an appropriate amount of crystal defects. Therefore, for example, it is possible to improve a breakdown voltage and reduce a leakage current.

Abstract: A short-distance radio communication in a steady situation and a long-distance radio communication in an unsteady situation are dynamically switched in a radio communication network, and a steady communication and an unsteady communication are realized through the same radio communication network without affecting the respective communication qualities. A radio communication network system includes radio terminals that enable a multihop communication, and a radio base station. The radio base station and the radio terminals communicate with each other by at least two kinds of transmission radio wave powers. The transmission radio wave power is variably controlled according to a measurement data value by sensors of the radio terminals, or a content of data received by a data communication.

Abstract: Provided are a device, a system, and a method in which redundancy is changed in accordance with a line state, and thus the optimal redundancy can be set while the current settings are compared to the previous settings. A communication device measures line quality information from a received packet, and generates a redundancy change instruction based on information regarding a line. In a case where the communication device acquires line quality information for the second and subsequent times, the communication device compares the previous redundancy change instruction and the previous line quality information, to the current line quality information, and sets redundancy. Thus, it is possible to suppress the occurrence of congestion and satisfy a target value of the line quality, and to search for a condition which causes the redundancy to be the minimum.

Abstract: An object of the disclosed invention is to provide a polling-based multihop communication system capable of achieving robust communication. Solving means thereof is a (multihop communication) wireless transmission system including, as wireless stations, a base station, a plurality of relay stations connected at multiple stages by using the base station as a root, and a plurality of terminals connected to the relay stations, in which the base station and the relay stations perform communication using polling in one or more service periods which have been allocated to each of the base and relay stations in time division in advance in a system cycle.

Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.

Abstract: It is necessary to increase the scale of a sensor network to achieve high resource exploration efficiency. On the other hand, since there are increasing needs to extend the area of an exploration region and to detect deeper geological stratum and crust structures more accurately, the large-scale sensor network needs to be operated for a long period of several weeks or longer. In order to solve the problem, a sensor unit needs to be turned on always to perform measurement always. However, an auxiliary measurement unit is activated intermittently since the auxiliary measurement unit needs to acquire data at necessary timings only. On the other hand, during collection and transmission of data and charging of a battery, a sensor terminal detects whether power is supplied from a data collection and charging device and automatically turns off the sensor unit and the auxiliary measurement unit to activate a data transmission unit.

Abstract: A method, for manufacturing a silicon carbide semiconductor device, includes: forming a silicon carbide epitaxial film on a silicon carbide substrate; flattening a surface of the epitaxial film by using chemical mechanical polishing such that the surface of the epitaxial film has an arithmetic mean roughness Ra of 0.3 nm or less; thermally oxidizing the surface of the epitaxial film to form a sacrificial oxide; removing the sacrificial oxide; and cleaning, by using deionized water, a surface of the epitaxial film exposed by the removing of the sacrificial oxide.

Abstract: The present invention relates to a method for producing a carbonate compound and methacrylic acid or an ester thereof, containing a step (a1) of obtaining hexachloroacetone and hydrogen chloride from acetone and chlorine molecule, a step (a2) of obtaining a dialkyl carbonate and chloroform from hexachloroacetone and an alkyl alcohol, a step (b1) of obtaining 1,1,1-trichloro-2-methyl-2-propanol from chloroform and acetone, a step (b2+b3 or b4) of obtaining methacrylic acid or an ester thereof and hydrogen chloride from 1,1,1-trichloro-2-methyl-2-propanol and water or an alcohol, and a step (c1 or c2) of obtaining chlorine molecule by reacting hydrogen chloride with oxygen molecule.

Abstract: Signals are maintained to be in phase at beam input ports of a Rotman lens antenna, and thus scanning at non-step antenna beam angles can be realized without increasing the number of input beams. The present invention provides an antenna beam scan module including: a Rotman lens that has plural beam ports and plural antenna ports; plural antenna elements; relative phase detectors that detect a relative phase difference between the signals input to the adjacent beam ports; phase shifters that offset the relative phase difference between the signals supplied to the adjacent beam ports on the basis of the relative phase difference detected by the relative phase detectors; and switches that select routes of the signals supplied to the beam ports through variable amplifiers, wherein the phase shifters are arranged on alternate routes through which the signals are supplied to the plural beam ports.

Abstract: A method of manufacturing a silicon carbide semiconductor device. The method includes providing an n-type semiconductor substrate having first and second principal surfaces, introducing an impurity from a first principal surface of the semiconductor substrate at a first position, activating the impurity to form a diffusion layer in the semiconductor substrate at a second position, implanting protons at a third position that is deeper from the first principal surface than the first position, the protons generating crystal defects in a region through which the protons pass, converting by thermal treating the protons into hydrogen induced donors to form an n-type field stop layer at a fourth position deeper from the first principal surface than the second position, reducing by the thermal treating the generated crystal defects to form an n-type crystal defect reduction region, and forming an electrode on the second principal surface after implanting the protons.

Abstract: A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.

Abstract: A method of producing a seminconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.

Abstract: The present invention relates to a method for producing a carbonate compound and methacrylic acid or an ester thereof, containing a step (a1) of obtaining hexachloroacetone and hydrogen chloride from acetone and chlorine molecule, a step (a2) of obtaining a dialkyl carbonate and chloroform from hexachloroacetone and an alkyl alcohol, a step (b1) of obtaining 1,1,1-trichloro-2-methyl-2-propanol from chloroform and acetone, a step (b2+b3 or b4) of obtaining methacrylic acid or an ester thereof and hydrogen chloride from 1,1,1-trichloro-2-methyl-2-propanol and water or an alcohol, and a step (c1 or c2) of obtaining chlorine molecule by reacting hydrogen chloride with oxygen molecule.

Abstract: A packet collision among a plurality of access points is avoided and QoS is ensured. An access point that shares a wireless channel with a plurality of access points to carry out communication is provided with a function for determining, based on information contained in a polling communication signal or a broadcast signal transmitted from another access point, an access point (preceding AP) that is to perform polling communication immediately before the own station to form a group within which the order of the polling communication is determined, and after determining that a polling communication period of the preceding AP has ended, starting the polling communication period of the own station in a wireless network.

Abstract: In a multi-hop radio communication network including a base station (a radio station connected to a management server), each radio station in the network is given a data transmission opportunity in turn according to a predetermined transmission order, and transmits data via broadcast or multicast upon occurrence of transmission timing. The radio station having received the data adds data of the radio station to the received data and then forwards the packet via broadcast or multicast when it is the radio station's turn for transmission.

Abstract: A semiconductor device includes an input electrode provided on a front surface of a semiconductor substrate of a first conductivity type and an output electrode provided on a rear surface of the semiconductor substrate. The device has reduced deterioration of electrical characteristics when manufactured by a method including introducing impurities into the rear surface of the semiconductor substrate; activating the impurities using a first annealing process to form a first semiconductor layer, which is a contact portion in contact with the output electrode, in a surface layer of the rear surface; radiating protons to the rear surface; and activating the protons radiated using a second annealing process to form a second semiconductor layer of the first conductivity type, which has a higher impurity concentration than the semiconductor substrate, in a region that is deeper than the first semiconductor layer from the rear surface of the semiconductor substrate.

Abstract: A p+ collector layer is provided in a rear surface of a semiconductor substrate which will be an n? drift layer and an n+ field stop layer is provided in a region which is deeper than the p+ collector layer formed on the rear surface side. A front surface element structure is formed on the front surface of the semiconductor substrate and then protons are radiated to the rear surface of the semiconductor substrate at an acceleration voltage corresponding to the depth at which the n+ field stop layer is formed. A first annealing process is performed at an annealing temperature corresponding to the proton irradiation to change the protons into donors, thereby forming a field stop layer. Then, annealing is performed using annealing conditions suitable for the conditions of a plurality of proton irradiation processes to recover each crystal defect formed by each proton irradiation process.