Abstract: Semiconductor devices and multiply-accumulate operation devices are disclosed. In one example, a semiconductor device includes synapses in which a nonvolatile variable resistance element taking a first resistance value and a second resistance value lower than the first resistance value and a fixed resistance element having a resistance value higher than the second resistance value are connected in series. An output line outputs a sum of currents flowing through the plurality of synapses.

Abstract: According to one embodiment, a refrigeration cycle apparatus includes a motor which including a plurality of phase windings in a mutually unconnected state, a first inverter which controls application of electric power to one ends of the phase windings, a second inverter which controls application of electric power to the other ends of the phase windings, switches connected between the other ends of the phase windings, and a motor controller which selectively sets one of an open-windings mode and a star-connection mode. The motor controller sets, at the time of startup of the motor, the open-windings mode.

Abstract: According to one embodiment, an outdoor unit equipped with a communication unit and a controller. The communication unit communicates data in a noncontact manner to an information terminal close to the outdoor unit. The controller permits the setting of data that has been input from the information terminal via the communication unit only during a fixed period of time after the outdoor unit has been turned on.

Abstract: Compound-semiconductor-wafer manufacturing whereby particle adherence, and obverse-surface oxidization and alteration are slight and the use of organic solvents is reduced. An adsorption pad is bonded to a polishing plate, and a wafer being adsorbed onto the adsorption pad without using wax is polished and thereafter stored within purified water without drying. Since storage is within purified water, particle adherence, and obverse-surface oxidization and alteration turn out to be slight, yielding a high-quality wafer. In the cleaning procedure following the aquatic storage, organic solvent washing is omitted. This allows the use/waste volume of noxious organic solvent to be reduced.

Abstract: Compound-semiconductor-wafer manufacturing whereby particle adherence, and obverse-surface oxidization and alteration are slight and the use of organic solvents is reduced. An adsorption pad is bonded to a polishing plate, and a wafer being adsorbed onto the adsorption pad without using wax is polished and thereafter stored within purified water without drying. Since storage is within purified water, particle adherence, and obverse-surface oxidization and alteration turn out to be slight, yielding a high-quality wafer. In the cleaning procedure following the aquatic storage, organic solvent washing is omitted. This allows the use/waste volume of noxious organic solvent to be reduced.

Abstract: In the present method, a group III-V compound semiconductor wafer includes a substrate consisting of a group III-V compound whose outer peripheral edge portion is so chamfered that its section has an arcuate shape substantially with a radius R, and an epitaxial layer consisting of a group III-V compound layer formed on the substrate. A portion of the wafer is removed at the outer peripheral edge thereof, up to a distance L from the original peripheral edge, and the distance L satisfies the expression R≦L≦3L. thereby an abnormally grown part of the epitaxial layer is reliably removed.