A semiconductor device that can perform product-sum operation with low power is provided. The semiconductor device includes a switching circuit. The switching circuit includes first to fourth terminals. The switching circuit has a function of selecting one of the third terminal and the fourth terminal as electrical connection destination of the first terminal, and selecting the other of the third terminal and the fourth terminal as electrical connection destination of the second terminal, on the basis of first data. The switching circuit includes a first transistor and a second transistor each having a back gate. The switching circuit has a function of determining a signal-transmission speed between the first terminal and one of the third terminal and the fourth terminal and a signal-transmission speed between the second terminal and the other of the third terminal and the fourth terminal on the basis of potentials of the back gates. The potentials are determined by second data. When signals are input to the first terminal and the second terminal, a time lag between the signals output from the third terminal and the fourth terminal is determined by the first data and the second data.

A semiconductor device that inhibits signal delay and can perform parallel product-sum operations is provided. The semiconductor device includes first to fourth registers, an adder, a multiplier, a selector, and a first memory unit. An output terminal of the first register is electrically connected to an input terminal of the second register, and an output terminal of the second register is electrically connected to a first input terminal of the multiplier. An output terminal of the multiplier is electrically connected to a first input terminal of the adder, and an output terminal of the adder is electrically connected to an input terminal of the third register. An output terminal of the third register is electrically connected to a first input terminal of the selector, and an output terminal of the selector is electrically connected to an input terminal of the fourth register, and the first memory unit is electrically connected to a second input terminal of the multiplier. The first memory unit has a function reading out first data corresponding to a context signal input to the first memory unit and inputting the first data to the second input terminal of the multiplier.

A semiconductor device in which variation of characteristics is small is provided. A second insulator, an oxide, a conductive layer, and an insulating layer are formed over a first insulator; a third insulator and fourth insulator are deposited to be in contact with the first insulator; a first opening reaching the oxide is formed in the conductive layer, the insulating layer, the third insulator, and the fourth insulator; a fifth insulator, a sixth insulator, and a conductor are formed in the first opening; a seventh insulator is deposited over the fourth insulator, the fifth insulator, and the sixth insulator; a mask is formed in a first region over the seventh insulator in a top view; oxygen is implanted into a second region not overlapping the first region in the top view; heat treatment is performed; a second opening reaching the fourth insulator is formed in the seventh insulator; and heat treatment is performed.

A semiconductor device with a small variation in transistor characteristics is provided. An oxide semiconductor film, a source electrode and a drain electrode over the oxide semiconductor film, an interlayer insulating film placed to cover the oxide semiconductor film, the source electrode, and the drain electrode, and a gate electrode over the oxide semiconductor film are included; an opening is formed overlapping with a region between the source electrode and the drain electrode in the interlayer insulating film; the gate electrode is placed in the opening in the interlayer insulating film; and the source electrode and the drain electrode include a conductive film having compressive stress.

Structures including III-V compound semiconductor-based devices and silicon-based devices integrated on a semiconductor substrate and methods of forming such structures. The structure includes a substrate having a device layer, a handle substrate, and a buried insulator layer between the handle substrate and the device layer. The structure includes a first semiconductor layer on the device layer in a first device region, and a second semiconductor layer on the device layer in a second device region. The first semiconductor layer contains a III-V compound semiconductor material, and the second semiconductor layer contains silicon. A first device structure includes a gate structure on the first semiconductor layer, and a second device structure includes a doped region in the second semiconductor layer. The doped region and the second semiconductor layer define a p-n junction.

A transistor includes a gate electrode, a gate dielectric layer covering the gate electrode, an active layer covering the gate dielectric layer and including a first metal oxide material, and source/drain electrodes disposed on the active layer and made of a second metal oxide material with an electron concentration of at least about 10.sup.18 cm.sup.−3. A semiconductor structure and a manufacturing method are also provided.

A semiconductor device with a small variation in characteristics is provided. The semiconductor device includes a first insulator, a transistor over the first insulator, a second insulator over the transistor, a third insulator over the second insulator, a fourth insulator over the third insulator, and an opening region. The opening region includes the second insulator, the third insulator over the second insulator, and the fourth insulator over the third insulator. The third insulator includes an opening reaching the second insulator. The fourth insulator is in contact with a top surface of the second insulator inside the opening.

A semiconductor device includes first to tenth transistors and first to fourth capacitors. Gates of the first and the fourth transistors are electrically connected to each other. First terminals of the first, second, fifth, and eighth transistors are electrically connected to a first terminal of the fourth capacitor. A second terminal of the fifth transistor is electrically connected to a gate of the sixth transistor and a first terminal of the second capacitor. A second terminal of the eighth transistor is electrically connected to a gate of the ninth transistor and a first terminal of the third capacitor. Gates of the second, seventh, and tenth transistors are electrically connected to first terminals of the third and fourth transistors and a first terminal of the first capacitor. First terminals of the sixth and seventh transistors are electrically connected to a second terminal of the second capacitor.

A semiconductor device that can be miniaturized or highly integrated is provided. The semiconductor device includes a capacitor, an electrode, and an interlayer film. The transistor includes a semiconductor layer, a gate, a source, and a drain; the transistor and the capacitor are placed to be embedded in the interlayer film. Below the semiconductor layer, one of the source and the drain is in contact with the electrode. Above the semiconductor layer, the other of the source and the drain is in contact with one electrode of the capacitor.

A minute transistor is provided. A transistor with low parasitic capacitance is provided. A transistor having high frequency characteristics is provided. A semiconductor device including the transistor is provided. A semiconductor device includes a first opening, a second opening, and a third opening which are formed by performing first etching and second etching. By the first etching, the first insulator is etched for forming the first opening, the second opening, and the third opening. By the second etching, the first metal oxide, the second insulator, the third insulator, the fourth insulator, the second metal oxide, and the fifth insulator are etched for forming the first opening; the first metal oxide, the second insulator, and the third insulator are etched for forming the second opening; and the first metal oxide is etched for forming the third opening.