Abstract: A semiconductor device includes a substrate, a semiconductor stacking portion formed on the substrate, a silicon nitride passivation film covering the surface of the semiconductor stacking portion, and oxygen atoms existing at an interface between the silicon nitride passivation film and the semiconductor stacking portion. The semiconductor stacking portion includes a plurality of nitride semiconductor layers. The interfacial oxygen content at the passivation film and stacking portion interface is 0.6×1015 oxygen atoms/cm2 or less.

Abstract: A method of forming a silicon nitride passivation film on a nitride semiconductor layer is comprising steps of, introducing a substrate including the nitride semiconductor layer into a reaction furnace, replacing an atmosphere in the reaction furnace from air to an ammonia (NH3) atmosphere or to a hydrogen (H2) atmosphere, raising a temperature in the reaction furnace to a first temperature, maintaining both the temperature in the reaction furnace at the first temperature and the atmosphere in the reaction furnace at the NH3 atmosphere or the H2 atmosphere for three minutes or more, lowering the temperature in the reaction furnace to a second temperature lower than the first temperature, and forming the silicon nitride passivation film by supplying dichlorosilane (SiH2Cl2) into the reaction furnace under the first pressure of 100 Pa or less in the reaction furnace.

Abstract: A semiconductor device made of primarily nitride semiconductor materials is disclosed. The semiconductor device includes a substrate; a semiconductor stack on the substrate; electrodes of a gate, a source, and a drain each provided on the semiconductor stack, where the gate electrode contains nickel (Ni); a Si compound covering surfaces of the semiconductor stack; an aluminum oxide (Al2O3) film covering the gate electrode exposed from the Si compound; and another Si compound covering the Al2O3 film and the Si compound exposed from the Al2O3 film. A feature of the semiconductor device of the invention is that the Al2O3 film exposes the Si compound at least between the gate electrode and the drain electrode.

Abstract: A technique to detect an eye potential of a wearer of an eyewear by using an electrode abutting on the glabella of the wearer has been known, but it is desirable to surely cause the electrode to abut on the glabella so as to prevent deterioration in the detection accuracy of detecting a biosignal indicating an eye potential, myogenic potential, brain wave or the like. In view of this, an eyewear including: a frame; a first electrode that abuts on a glabella of a wearer of the eyewear; and an electrode holding unit that holds the first electrode such that a distance between the frame and the first electrode is changeable is included.

Abstract: A technique to detect an eye potential of a wearer of an eyewear by using an electrode abutting on the glabella of the wearer has been known, but it is desirable to surely cause the electrode to abut on the glabella so as to prevent deterioration in the detection accuracy of detecting a biosignal indicating an eye potential, myogenic potential, brain wave or the like. In view of this, an eyewear including: a frame; a first electrode that abuts on a glabella of a wearer of the eyewear; and an electrode holding unit that holds the first electrode such that a distance between the frame and the first electrode is changeable is included.

Abstract: A technique to detect an eye potential of a wearer of an eyewear by using an electrode abutting on the glabella of the wearer has been known, but it is desirable to surely cause the electrode to abut on the glabella so as to prevent deterioration in the detection accuracy of detecting a biosignal indicating an eye potential, myogenic potential, brain wave or the like. In view of this, an eyewear including: a frame; a first electrode that abuts on a glabella of a wearer of the eyewear; and an electrode holding unit that holds the first electrode such that a distance between the frame and the first electrode is changeable is included.

Abstract: A technique to detect an eye potential of a wearer of an eyewear by using an electrode abutting on the glabella of the wearer has been known, but it is desirable to surely cause the electrode to abut on the glabella so as to prevent deterioration in the detection accuracy of detecting a biosignal indicating an eye potential, myogenic potential, brain wave or the like. In view of this, an eyewear including: a frame; a first electrode that abuts on a glabella of a wearer of the eyewear; and an electrode holding unit that holds the first electrode such that a distance between the frame and the first electrode is changeable is included.

Abstract: A semiconductor device of the invention includes an n-GaN layer provided on a substrate, a channel layer provided in contact with the upper surface of the n-GaN layer, an electron supply layer which is provided on the channel layer, and a gate electrode, a source electrode, and a drain electrode which are provided on the electron supply layer. The gate electrode is in contact with an underlying layer made from a nitride semiconductor. The semiconductor device has a ratio defined by the equation L/d1?7, where L is the width of the gate electrode in contact with the underlying layer in a direction between the source electrode and drain electrode; and d1 is the distance between a surface of the n-type gallium nitride layer and a boundary between the gate electrode and the underlying layer.

Abstract: A vertical semiconductor device in which pinch-off characteristics and breakdown voltage characteristics can be stably improved by fixing the electric potential of a p-type GaN barrier layer with certainty is provided. The semiconductor device includes a GaN-based stacked layer having an opening, a regrown layer including a channel located so as to cover a wall surface of the opening, an n+-type source layer that is in ohmic contact with the source electrode, a p-type GaN barrier layer, and a p+-type GaN-based supplementary layer located between the p-type GaN barrier layer and the n+-type source layer. The p+-type GaN-based supplementary layer and the n+-type source layer form a tunnel junction to fix the electric potential of the p-type GaN barrier layer at a source potential.

Abstract: It is an object to improve the breakdown voltage characteristics of a vertical semiconductor device having an opening and including a channel formed of two-dimensional electron gas in the opening. A GaN-based stacked layer 15 includes n?-type GaN drift layer 4/p-type GaN barrier layer 6/n+-type GaN contact layer 7. An opening 28 extends from a top layer and reaches the n?-type GaN drift layer 4. The semiconductor device includes a regrown layer 27 located so as to cover a wall surface and a bottom portion of the opening, the regrown layer 27 including an electron drift layer 22 and an electron source layer 26, a source electrode S located around the opening, a gate electrode G located on the regrown layer in the opening, and a bottom insulating layer 37 located in the bottom portion of the opening.

Abstract: It is an object to improve the breakdown voltage characteristics of a vertical semiconductor device having an opening and including a channel formed of two-dimensional electron gas in the opening. The vertical semiconductor device includes a GaN-based stacked layer 15 having an opening 28 and the GaN-based stacked layer 15 includes n-type GaN-based drift layer 4/p-type GaN-based barrier layer 6/n-type GaN-based contact layer 7. The vertical semiconductor device includes a regrown layer 27 located so as to cover the opening, the regrown layer 27 including an electron drift layer 22 and an electron supply layer 26, a source electrode S, and a gate electrode G located on the regrown layer. The gate electrode G covers a portion having a length corresponding to the thickness of the p-type GaN-based barrier layer and is terminated at a position on the wall surface, the position being away from the bottom portion of the opening.

Abstract: In a vertical semiconductor device including a channel in an opening, a semiconductor device whose high-frequency characteristics can be improved and a method for producing the semiconductor device are provided. The semiconductor device includes n-type GaN-based drift layer 4/p-type GaN-based barrier layer 6/n-type GaN-based contact layer 7. An opening 28 extends from a top layer and reaches the n-type GaN-based drift layer. The semiconductor device includes a regrown layer 27 located so as to cover the opening, the regrown layer 27 including an electron drift layer 22 and an electron supply layer 26, a source electrode S, a drain electrode D, and a gate electrode G located on the regrown layer. Assuming that the source electrode serving as one electrode and the drain electrode serving as the other electrode constitute a capacitor, the semiconductor device includes a capacitance-decreasing structure that decreases the capacitance of the capacitor.

Abstract: A semiconductor device of the invention includes an n-GaN layer provided on a substrate, a channel layer provided in contact with the upper surface of the n-GaN layer, an electron supply layer which is provided on the channel layer, and a gate electrode, a source electrode, and a drain electrode which are provided on the electron supply layer. The gate electrode is in contact with a underlying layer made from a nitride semiconductor. The semiconductor device has a ratio defined by the equation L/d1>=7, where L=the width of the gate electrode in contact with the underlying layer in a direction between the source electrode and drain electrode; d1 the distance between a surface of the n-type gallium nitride layer and a boundary between the gate electrode and the underlying layer.

Abstract: There is provided a vertical GaN-based semiconductor device in which the on-resistance can be decreased while the breakdown voltage characteristics are improved using a p-type GaN barrier layer. The semiconductor device includes a regrown layer 27 including a channel located on a wall surface of an opening 28, a p-type barrier layer 6 whose end face is covered, a source layer 7 that is in contact with the p-type barrier layer, a gate electrode G located on the regrown layer, and a source electrode S located around the opening. In the semiconductor device, the source layer has a superlattice structure that is constituted by a stacked layer including a first layer (a layer) having a lattice constant smaller than that of the p-type barrier layer and a second layer (b layer) having a lattice constant larger than that of the first layer.

Abstract: A semiconductor device includes source electrodes having source fingers, drain electrodes having drain fingers, and gate electrodes having bent portions between steps formed in stepwise side portions of source fingers and steps formed in stepwise side portions of drain fingers and being bent in the bent portions along the source fingers and the drain fingers. A shape of the stepwise side portion of one source finger and that of the stepwise portion of the corresponding drain finger are symmetrical about a midpoint of an imaginary line that connects the other end of the source finger and the other end of the corresponding drain finger.

Abstract: In a vertical semiconductor device including a channel in an opening, a semiconductor device whose high-frequency characteristics can be improved and a method for producing the semiconductor device are provided. The semiconductor device includes n-type GaN-based drift layer 4/p-type GaN-based barrier layer 6/n-type GaN-based contact layer 7. An opening 28 extends from a top layer and reaches the n-type GaN-based drift layer. The semiconductor device includes a regrown layer 27 located so as to cover the opening, the regrown layer 27 including an electron drift layer 22 and an electron supply layer 26, a source electrode S, a drain electrode D, and a gate electrode G located on the regrown layer. Assuming that the source electrode serving as one electrode and the drain electrode serving as the other electrode constitute a capacitor, the semiconductor device includes a capacitance-decreasing structure that decreases the capacitance of the capacitor.

Abstract: There is provided a semiconductor device or the like which includes a channel and a gate electrode in an opening and in which electric field concentration near a bottom portion of the opening can be reduced. The semiconductor device includes n?-type GaN drift layer 4/p-type GaN barrier layer 6/n+-type GaN contact layer. An opening 28 extends from the top layer and reaches the n-type GaN-based drift layer. The semiconductor device includes a regrown layer 27 located in the opening, the regrown layer 27 including an electron supply layer 26 and an electron drift layer 22, a source electrode S, a drain electrode D, a gate electrode G located on the regrown layer, and a semiconductor impurity adjustment region 31 disposed in the bottom portion of the opening. The impurity adjustment region 31 is a region that promotes a potential drop from the drain electrode side to the gate electrode side in a potential distribution in an off-state.

Abstract: It is an object to improve the breakdown voltage characteristics of a vertical semiconductor device having an opening and including a channel formed of two-dimensional electron gas in the opening. A GaN-based stacked layer 15 includes n?-type GaN drift layer 4/p-type GaN barrier layer 6/n+-type GaN contact layer 7. An opening 28 extends from a top layer and reaches the n?-type GaN drift layer 4. The semiconductor device includes a regrown layer 27 located so as to cover a wall surface and a bottom portion of the opening, the regrown layer 27 including an electron drift layer 22 and an electron source layer 26, a source electrode S located around the opening, a gate electrode G located on the regrown layer in the opening, and a bottom insulating layer 37 located in the bottom portion of the opening.

Abstract: It is an object to improve the breakdown voltage characteristics of a vertical semiconductor device having an opening and including a channel formed of two-dimensional electron gas in the opening. The vertical semiconductor device includes a GaN-based stacked layer 15 having an opening 28 and the GaN-based stacked layer 15 includes n-type GaN-based drift layer 4/p-type GaN-based barrier layer 6/n-type GaN-based contact layer 7. The vertical semiconductor device includes a regrown layer 27 located so as to cover the opening, the regrown layer 27 including an electron drift layer 22 and an electron supply layer 26, a source electrode S, and a gate electrode G located on the regrown layer. The gate electrode G covers a portion having a length corresponding to the thickness of the p-type GaN-based barrier layer and is terminated at a position on the wall surface, the position being away from the bottom portion of the opening.

Abstract: There is provided a vertical GaN-based semiconductor device in which the on-resistance can be decreased while the breakdown voltage characteristics are improved using a p-type GaN barrier layer. The semiconductor device includes a regrown layer 27 including a channel located on a wall surface of an opening 28, a p-type barrier layer 6 whose end face is covered, a source layer 7 that is in contact with the p-type barrier layer, a gate electrode G located on the regrown layer, and a source electrode S located around the opening. In the semiconductor device, the source layer has a superlattice structure that is constituted by a stacked layer including a first layer (a layer) having a lattice constant smaller than that of the p-type barrier layer and a second layer (b layer) having a lattice constant larger than that of the first layer.