Abstract: In a semiconductor device including a transistor in which an oxide semiconductor layer, a gate insulating layer, and a gate electrode layer on side surfaces of which sidewall insulating layers are provided are stacked in this order, a source electrode layer and a drain electrode layer are provided in contact with the oxide semiconductor layer and the sidewall insulating layers. In a process for manufacturing the semiconductor device, a conductive layer and an interlayer insulating layer are stacked to cover the oxide semiconductor layer, the sidewall insulating layers, and the gate electrode layer. Then, parts of the interlayer insulating layer and the conductive layer over the gate electrode layer are removed by a chemical mechanical polishing method, so that a source electrode layer and a drain electrode layer are formed. Before formation of the gate insulating layer, cleaning treatment is performed on the oxide semiconductor layer.

Abstract: A semiconductor device with favorable electrical characteristics is provided. The semiconductor device includes an insulating layer, a semiconductor layer over the insulating layer, a source electrode layer and a drain electrode layer electrically connected to the semiconductor layer, a gate insulating film over the semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode layer overlapping with part of the semiconductor layer, part of the source electrode layer, and part of the drain electrode layer with the gate insulating film therebetween. A cross section of the semiconductor layer in the channel width direction is substantially triangular or substantially trapezoidal. The effective channel width is shorter than that for a rectangular cross section.

Abstract: The on-state characteristics of a transistor are improved and thus, a semiconductor device capable of high-speed response and high-speed operation is provided. A highly reliable semiconductor device showing stable electric characteristics is made. The semiconductor device includes a transistor including a first oxide layer; an oxide semiconductor layer over the first oxide layer; a source electrode layer and a drain electrode layer in contact with the oxide semiconductor layer; a second oxide layer over the oxide semiconductor layer; a gate insulating layer over the second oxide layer; and a gate electrode layer over the gate insulating layer. An end portion of the second oxide layer and an end portion of the gate insulating layer overlap with the source electrode layer and the drain electrode layer.

Abstract: A semiconductor device includes a first insulating layer over a substrate, a first metal oxide layer over the first insulating layer, an oxide semiconductor layer over the first metal oxide layer, a second metal oxide layer over the oxide semiconductor layer, a gate insulating layer over the second metal oxide layer, a second insulating layer over the second metal oxide layer, and a gate electrode layer over the gate insulating layer. The gate insulating layer includes a region in contact with a side surface of the gate electrode layer. The second insulating layer includes a region in contact with the gate insulating layer. The oxide semiconductor layer includes first to third regions. The first region includes a region overlapping with the gate electrode layer. The second region, which is between the first and third regions, includes a region overlapping with the gate insulating layer or the second insulating layer.

Abstract: An object is to establish a processing technique in manufacture of a semiconductor device in which an oxide semiconductor is used. A gate electrode is formed over a substrate, a gate insulating layer is formed over the gate electrode, an oxide semiconductor layer is formed over the gate insulating layer, the oxide semiconductor layer is processed by wet etching to form an island-shaped oxide semiconductor layer, a conductive layer is formed to cover the island-shaped oxide semiconductor layer, the conductive layer is processed by dry etching to form a source electrode, and a drain electrode and part of the island-shaped oxide semiconductor layer is removed by dry etching to form a recessed portion in the island-shaped oxide semiconductor layer.

Abstract: To give favorable electrical characteristics to a semiconductor device. The semiconductor device includes an insulating layer, a semiconductor layer over the insulating layer, a pair of electrodes over the semiconductor layer and each electrically connected to the semiconductor layer, a gate electrode over the semiconductor layer, and a gate insulating layer between the semiconductor layer and the gate electrode. The insulating layer includes an island-shaped projecting portion. A top surface of the projecting portion of the insulating layer is in contact with a bottom surface of the semiconductor layer, and is positioned on an inner side of the semiconductor layer when seen from above. The pair of electrodes covers part of a top surface and part of side surfaces of the semiconductor layer. Furthermore, the gate electrode and the gate insulating layer cover side surfaces of the projecting portion of the insulating layer.

Abstract: To provide a highly reliable semiconductor device using an oxide semiconductor. The semiconductor device includes a first electrode layer; a second electrode layer positioned over the first electrode layer and including a stacked-layer structure of a first conductive layer and a second conductive layer; and an oxide semiconductor film and an insulating film positioned between the first electrode layer and the second electrode layer in a thickness direction. The first conductive layer and the insulating film have a first opening portion in a region overlapping with the first electrode layer, The oxide semiconductor film has a second opening portion in a region overlapping with the first opening portion. The second conductive layer is in contact with the first electrode layer exposed in the first opening portion and the second opening portion.

Abstract: To provide a semiconductor device which occupies a small area and is highly integrated. The semiconductor device includes an oxide semiconductor layer, an electrode layer, and a contact plug. The electrode layer includes one end portion in contact with the oxide semiconductor layer and the other end portion facing the one end portion. The other end portion includes a semicircle notch portion when seen from the above. The contact plug is in contact with the semicircle notch portion.

Abstract: First to third insulators are successively formed in this order over a first conductor over a semiconductor substrate; a hard mask with a first opening is formed thereover; a resist mask with a second opening is formed thereover; a third opening is formed in the third insulator; a fourth opening is formed in the second insulator; the resist mask is removed; a fifth opening is formed in the first to third insulators; a second conductor is formed to cover an inner wall and a bottom surface of the fifth opening; a third conductor is formed thereover; polishing treatment is performed so that the hard mask is removed, and that levels of top surfaces of the second and third conductors and the third insulator are substantially equal to each other; and an oxide semiconductor is formed thereover. The second insulator is less permeable to hydrogen than the first and third insulators, the second conductor is less permeable to hydrogen than the third conductor.

Abstract: When a transistor having bottom gate bottom contact structure is manufactured, for example, a conductive layer constituting a source and a drain has a three-layer structure and two-step etching is performed. In the first etching process, an etching method in which the etching rates for at least the second film and the third film are high is employed, and the first etching process is performed until at least the first film is exposed. In the second etching process, an etching method in which the etching rate for the first film is higher than that in the first etching process and the etching rate for a “layer provided below and in contact with the first film” is lower than that in the first etching process is employed. The side wall of the second film is slightly etched when a resist mask is removed after the second etching process.

Abstract: The semiconductor device includes a first layer including a first transistor, a second layer including a first insulating film over the first layer, a third layer including a second insulating film over the second layer, and a fourth layer including a second transistor over the third layer. A first conductive film electrically connects the first transistor and the second transistor to each other through an opening provided in the first insulating film. A second conductive film electrically connects the first transistor, the second transistor, and the first conductive film to one another through an opening provided in the second insulating film. A channel formation region of the first transistor includes a single crystal semiconductor. A channel formation region of the second transistor includes an oxide semiconductor. The width of a bottom surface of the second conductive film is 5 nm or less.

Abstract: In a semiconductor device including a transistor in which an oxide semiconductor layer, a gate insulating layer, and a gate electrode layer on side surfaces of which sidewall insulating layers are provided are stacked in this order, a source electrode layer and a drain electrode layer are provided in contact with the oxide semiconductor layer and the sidewall insulating layers. In a process for manufacturing the semiconductor device, a conductive layer and an interlayer insulating layer are stacked to cover the oxide semiconductor layer, the sidewall insulating layers, and the gate electrode layer. Then, parts of the interlayer insulating layer and the conductive layer over the gate electrode layer are removed by a chemical mechanical polishing method, so that a source electrode layer and a drain electrode layer are formed. Before formation of the gate insulating layer, cleaning treatment is performed on the oxide semiconductor layer.

Abstract: The on-state characteristics of a transistor are improved and thus, a semiconductor device capable of high-speed response and high-speed operation is provided. A highly reliable semiconductor device showing stable electric characteristics is made. The semiconductor device includes a transistor including a first oxide layer; an oxide semiconductor layer over the first oxide layer; a source electrode layer and a drain electrode layer in contact with the oxide semiconductor layer; a second oxide layer over the oxide semiconductor layer; a gate insulating layer over the second oxide layer; and a gate electrode layer over the gate insulating layer. An end portion of the second oxide layer and an end portion of the gate insulating layer overlap with the source electrode layer and the drain electrode layer.

Abstract: A minute transistor is provided. A transistor with low parasitic capacitance is provided. A transistor having high frequency characteristics is provided. A transistor having a high on-state current is provided. A semiconductor device including the transistor is provided. A semiconductor device having a high degree of integration is provided. A semiconductor device including an oxide semiconductor; a second insulator; a second conductor; a third conductor; a fourth conductor; a fifth conductor; a first conductor and a first insulator embedded in an opening portion formed in the second insulator, the second conductor, the third conductor, the fourth conductor, and the fifth conductor; a region where a side surface and a bottom surface of the second conductor are in contact with the fourth conductor; and a region where a side surface and a bottom surface of the third conductor are in contact with the fifth conductor.

Abstract: An object of an embodiment of the present invention is to provide a semiconductor device including a normally-off oxide semiconductor element whose characteristic variation is small in the long term. A cation containing one or more elements selected from oxygen and halogen is added to an oxide semiconductor layer, thereby suppressing elimination of oxygen, reducing hydrogen, or suppressing movement of hydrogen. Accordingly, carriers in the oxide semiconductor can be reduced and the number of the carriers can be kept constant in the long term. As a result, the semiconductor device including the normally-off oxide semiconductor element whose characteristic variation is small in the long term can be provided.

Abstract: To provide a highly reliable semiconductor device using an oxide semiconductor. The semiconductor device includes a first electrode layer; a second electrode layer positioned over the first electrode layer and including a stacked-layer structure of a first conductive layer and a second conductive layer; and an oxide semiconductor film and an insulating film positioned between the first electrode layer and the second electrode layer in a thickness direction. The first conductive layer and the insulating film have a first opening portion in a region overlapping with the first electrode layer. The oxide semiconductor film has a second opening portion in a region overlapping with the first opening portion. The second conductive layer is in contact with the first electrode layer exposed in the first opening portion and the second opening portion.

Abstract: A semiconductor device which includes a transistor having a miniaturized structure is provided. A first insulator is provided over a stack in which a semiconductor, a first conductor, and a second conductor are stacked in this order. Over the first insulator, an etching mask is formed. Using the etching mask, the first insulator and the second conductor are etched until the first conductor is exposed. After etching the first conductor until the semiconductor is exposed so as to form a groove having a smaller width than the second conductor, a second insulator and a third conductor are formed sequentially.

Abstract: A semiconductor device having a transistor including an oxide semiconductor film is disclosed. In the semiconductor device, the oxide semiconductor film is provided along a trench formed in an insulating layer. The trench includes a lower end corner portion and an upper end corner portion having a curved shape with a curvature radius of longer than or equal to 20 nm and shorter than or equal to 60 nm, and the oxide semiconductor film is provided in contact with a bottom surface, the lower end corner portion, the upper end corner portion, and an inner wall surface of the trench. The oxide semiconductor film includes a crystal having a c-axis substantially perpendicular to a surface at least over the upper end corner portion.

Abstract: The semiconductor device includes a first layer including a first transistor, a second layer including a first insulating film over the first layer, a third layer including a second insulating film over the second layer, and a fourth layer including a second transistor over the third layer. A first conductive film electrically connects the first transistor and the second transistor to each other through an opening provided in the first insulating film. A second conductive film electrically connects the first transistor, the second transistor, and the first conductive film to one another through an opening provided in the second insulating film. A channel formation region of the first transistor includes a single crystal semiconductor. A channel formation region of the second transistor includes an oxide semiconductor. The width of a bottom surface of the second conductive film is 5 nm or less.

Abstract: A minute transistor is provided. A transistor with small parasitic capacitance is provided. A transistor with high frequency characteristics is provided. A semiconductor device including the transistor is provided. A semiconductor device includes an oxide semiconductor, a first conductor and a second insulator embedded in a first insulator, a second conductor and a third conductor. Edges of the second conductor and the third conductor facing each other each has a taper angle of 30 degree or more and 90 degree or less.