Abstract: According to one embodiment, an isolator includes first and second electrodes, first and second insulating portions, and a first dielectric portion. The first insulating portion is provided on the first electrode. The second electrode is provided on the first insulating portion. The second insulating portion is provided around the second electrode along a first plane perpendicular to a first direction. The second insulating portion contacts the second electrode. The first dielectric portion is provided between the first and second insulating portions. At least a portion of the first dielectric portion contacts the second electrode and is positioned around the second electrode along the first plane. A distance between a lower end of the second electrode and a first interface between the first dielectric portion and the second insulating portion is less than a distance between the first interface and an upper end of the second electrode.

Abstract: According to one embodiment, an isolator includes first and second electrodes, first and second insulating portions, and a first dielectric portion. The first insulating portion is provided on the first electrode. The second electrode is provided on the first insulating portion. The second insulating portion is provided around the second electrode along a first plane perpendicular to a first direction. The second insulating portion contacts the second electrode. The first dielectric portion is provided between the first and second insulating portions. At least a portion of the first dielectric portion contacts the second electrode and is positioned around the second electrode along the first plane. A distance between a lower end of the second electrode and a first interface between the first dielectric portion and the second insulating portion is less than a distance between the first interface and an upper end of the second electrode.

Abstract: An isolator includes a first electrode; a first insulating portion on the first electrode; a second electrode on the first insulating portion; a second insulating portion around the second electrode; and a first dielectric portion on the second electrode and the second insulating portion. The second insulating portion is provided along a first plane perpendicular to a first direction from the first electrode toward the second electrode. The second electrode including a bottom surface facing the first insulating portion, an upper surface facing the first dielectric portion, a first side surface connected to the bottom surface, and a second side surface connected to the upper surface and the first side surface. The upper surface is wider than the bottom surface in a second direction along the first plane. The first side surface is tilted with respect to the bottom surface and the second side surface.

Abstract: An isolator includes a first electrode; a first insulating portion on the first electrode; a second electrode on the first insulating portion; a second insulating portion around the second electrode; and a first dielectric portion on the second electrode and the second insulating portion. The second insulating portion is provided along a first plane perpendicular to a first direction from the first electrode toward the second electrode. The second electrode including a bottom surface facing the first insulating portion, an upper surface facing the first dielectric portion, a first side surface connected to the bottom surface, and a second side surface connected to the upper surface and the first side surface. The upper surface is wider than the bottom surface in a second direction along the first plane. The first side surface is tilted with respect to the bottom surface and the second side surface.

Abstract: An isolator includes a first electrode; a first insulating portion on the first electrode; a second electrode on the first insulating portion; a second insulating portion around the second electrode; and a first dielectric portion on the second electrode and the second insulating portion. The second insulating portion is provided along a first plane perpendicular to a first direction from the first electrode toward the second electrode. The second electrode including a bottom surface facing the first insulating portion, an upper surface facing the first dielectric portion, a first side surface connected to the bottom surface, and a second side surface connected to the upper surface and the first side surface. The upper surface is wider than the bottom surface in a second direction along the first plane. The first side surface is tilted with respect to the bottom surface and the second side surface.

Abstract: An isolator includes a first electrode; a first insulating portion on the first electrode; a second electrode on the first insulating portion; a second insulating portion around the second electrode; and a first dielectric portion on the second electrode and the second insulating portion. The second insulating portion is provided along a first plane perpendicular to a first direction from the first electrode toward the second electrode. The second electrode including a bottom surface facing the first insulating portion, an upper surface facing the first dielectric portion, a first side surface connected to the bottom surface, and a second side surface connected to the upper surface and the first side surface. The upper surface is wider than the bottom surface in a second direction along the first plane. The first side surface is tilted with respect to the bottom surface and the second side surface.

Abstract: An isolator includes a first electrode; a first insulating portion on the first electrode; a second electrode on the first insulating portion; a second insulating portion around the second electrode; and a first dielectric portion on the second electrode and the second insulating portion. The second insulating portion is provided along a first plane perpendicular to a first direction from the first electrode toward the second electrode. The second electrode including a bottom surface facing the first insulating portion, an upper surface facing the first dielectric portion, a first side surface connected to the bottom surface, and a second side surface connected to the upper surface and the first side surface. The upper surface is wider than the bottom surface in a second direction along the first plane. The first side surface is tilted with respect to the bottom surface and the second side surface.

Abstract: An isolator includes a substrate; a first planar coil provided above the substrate and along a surface of the substrate; a first insulating portion on the first planar coil; a second planar coil on the first insulating portion; and a metal layer above the first insulating portion. The first planar coil, the second planar coil, and the metal layer are arranged in a first direction perpendicular to the surface of the substrate. The first planar coil and the second planar coil each having a center and an outer perimeter in a second direction along the surface of the substrate. A distance in the second direction from the center of the first planar coil to the outer perimeter of the first planar coil is less than a distance in the second direction from the center of the second planar coil to the outer perimeter of the second planar coil.

Abstract: According to one embodiment, an isolator includes first and second electrodes, first and second insulating portions, and a first dielectric portion. The first insulating portion is provided on the first electrode. The second electrode is provided on the first insulating portion. The second insulating portion is provided around the second electrode along a first plane perpendicular to a first direction. The second insulating portion contacts the second electrode. The first dielectric portion is provided between the first and second insulating portions. At least a portion of the first dielectric portion contacts the second electrode and is positioned around the second electrode along the first plane. A distance between a lower end of the second electrode and a first interface between the first dielectric portion and the second insulating portion is less than a distance between the first interface and an upper end of the second electrode.

Abstract: Provided is a semiconductor device including a DC/DC converter circuit, wherein the DC/DC converter circuit includes a transistor of a normally-off type, having a first drain electrode connected town input terminal and a first source electrode connected to an output terminal, which is formed in a first compound semiconductor substrate having a two-dimensional electron gas layer, and a transistor having a second drain electrode connected to the first source electrode and a grounded second source electrode.

Abstract: An electrode comes in ohmic contact with an AlGaN layer. A semiconductor device SD has a nitride semiconductor layer GN2, and an AlxGa(1-x)N layer AGN (hereinafter referred to as “AlGaN layer AGN), and Al electrodes DE, SE. in the AlGaN layer AGN, 0<x?0.2 is satisfied. Also, both of a concentration of a p-type impurity and a concentration of an n-type impurity in the AlGaN layer AGN are 1×1016 cm?3 or lower. In this example, the p-type impurity is exemplified by, for example, Be, C, and Mg, and the n-type impurity is exemplified by Si, S, and Se. Also, the Al electrodes DE and SE are connected to the AlGaN layer AGN. Because a composition ratio of Al is limited to the above-mentioned range, the Al electrodes DE and SE are brought into ohmic contact with the AlGaN layer AGN.

Abstract: Provided is a semiconductor device including a DC/DC converter circuit, wherein the DC/DC converter circuit includes a transistor of a normally-off type, having a first drain electrode connected town input terminal and a first source electrode connected to an output terminal, which is formed in a first compound semiconductor substrate having a two-dimensional electron gas layer, and a transistor having a second drain electrode connected to the first source electrode and a grounded second source electrode.

Abstract: Provided is a semiconductor device including: a DC/DC converter circuit, wherein the DC/DC converter circuit includes a transistor of a normally-off type, having a first drain electrode connected town input terminal and a first source electrode connected to an output terminal, which is formed in a first compound semiconductor substrate having a two-dimensional electron gas layer, and a transistor having a second drain electrode connected to the first source electrode and a grounded second source electrode.

Abstract: To improve performance of a semiconductor device. For example, on the assumption that a superlattice layer is inserted between a buffer layer and a channel layer, a concentration of acceptors introduced into nitride semiconductor layers forming a part of the superlattice layer is higher than a concentration of acceptors introduced into nitride semiconductor layers forming the other part of the superlattice layer. That is, the concentration of acceptors introduced into the nitride semiconductor layers having a small band gap is higher than the concentration of acceptors introduced into the nitride semiconductor layers having a large band gap.

Abstract: Provided is a semiconductor device including: a DC/DC converter circuit, wherein the DC/DC converter circuit includes a transistor of a normally-off type, having a first drain electrode connected town input terminal and a first source electrode connected to an output terminal, which is formed in a first compound semiconductor substrate having a two-dimensional electron gas layer, and a transistor having a second drain electrode connected to the first source electrode and a grounded second source electrode.

Abstract: The reliability of a field effect transistor made of a nitride semiconductor material is improved. An ohmic electrode includes a plurality of unit electrodes isolated to be separated from each other. With this configuration, an on-state current can be prevented from flowing in the unit electrodes in a y-axial direction (negative direction). Further, in the respective unit electrodes, a current density of the on-state current flowing in the y-axial direction (negative direction) can be prevented from increasing. As a result, an electromigration resistance of the ohmic electrode can be improved.

Abstract: A semiconductor device including a DC/DC converter circuit, in which the DC/DC converter circuit includes a transistor of a normally-off type, having a first drain electrode connected to an input terminal and a first source electrode connected to an output terminal, which is formed in a first compound semiconductor substrate having a two-dimensional electron gas layer, and a transistor having a second drain electrode connected to the first source electrode and a grounded second source electrode.

Abstract: The reliability of a field effect transistor made of a nitride semiconductor material is improved. An ohmic electrode includes a plurality of unit electrodes isolated to be separated from each other. With this configuration, an on-state current can be prevented from flowing in the unit electrodes in a y-axial direction (negative direction). Further, in the respective unit electrodes, a current density of the on-state current flowing in the y-axial direction (negative direction) can be prevented from increasing. As a result, an electromigration resistance of the ohmic electrode can be improved.

Abstract: An electrode comes in ohmic contact with an AlGaN layer. A semiconductor device SD has a nitride semiconductor layer GN2, and an AlxGa(1?x)N layer AGN (hereinafter referred to as “AlGaN layer AGN), and Al electrodes DE, SE. in the AlGaN layer AGN, 0<X?0.2 is satisfied. Also, both of a concentration of a p-type impurity and a concentration of an n-type impurity in the AlGaN layer AGN are 1×1016 cm?3 or lower. In this example, the p-type impurity is exemplified by, for example, Be, C, and Mg, and the n-type impurity is exemplified by Si, S, and Se. Also, the Al electrodes DE and SE are connected to the AlGaN layer AGN. Because a composition ratio of Al is limited to the above-mentioned range, the Al electrodes DE and SE are brought into ohmic contact with the AlGaN layer AGN.

Abstract: To improve performance of a semiconductor device. For example, on the assumption that a superlattice layer is inserted between a buffer layer and a channel layer, a concentration of acceptors introduced into nitride semiconductor layers forming a part of the superlattice layer is higher than a concentration of acceptors introduced into nitride semiconductor layers forming the other part of the superlattice layer. That is, the concentration of acceptors introduced into the nitride semiconductor layers having a small band gap is higher than the concentration of acceptors introduced into the nitride semiconductor layers having a large band gap.