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: Provided is a III nitride semiconductor electronic device having a structure capable of reducing leakage current. A laminate 11 includes a substrate 13 and a III nitride semiconductor epitaxial film 15. The substrate 13 is made of a III nitride semiconductor having a carrier concentration of more than 1×1018 cm?3. The epitaxial structure 15 includes a III nitride semiconductor epitaxial film 17. A first face 13a of the substrate 13 is inclined at an angle ? of more than 5 degrees with respect to an axis Cx extending in a direction of the c-axis. A normal vector VN and a c-axis vector VC make the angle ?. The III nitride semiconductor epitaxial film 17 includes first, second and third regions 17a, 17b and 17c arranged in order in a direction of a normal to the first face 13a. A dislocation density of the third region 17c is smaller than that of the first region 17a. A dislocation density of the second region 17b is smaller than that of the substrate 13.

Abstract: There are provided a semiconductor device in which a drain leak current can be reduced in the transistor operation while high vertical breakdown voltage is achieved and a method for producing the semiconductor device. In the semiconductor device, an opening 28 that extends from an n+-type contact layer 8 and reaches an n-type drift layer 4 through a p-type barrier layer 6 is formed. The semiconductor device includes a regrown layer 27 located so as to cover portions of the p-type barrier layer 6 and the like that are exposed to the opening, the regrown layer 27 including an undoped GaN channel layer 22 and a carrier supply layer 26; an insulating layer 9 located so as to cover the regrown layer 27; and a gate electrode G located on the insulating layer 9. In the p-type barrier layer, the Mg concentration A (cm?3)and the hydrogen concentration B (cm?3) satisfy 0.1<B/A<0.9 . . . (1).

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 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: A silicon carbide substrate includes a base layer made of silicon carbide, silicon carbide layers made of single-crystal silicon carbide and arranged side by side on the base layer when viewed in plan view, and a filling portion made of silicon carbide and filling a gap formed between the adjacent silicon carbide layers. The filling portion has a surface roughness of not more than 50 ?m in RMS value.

Abstract: The present method of forming a nitride semiconductor epitaxial layer includes the steps of growing at least one layer of nitride semiconductor epitaxial layer on a nitride semiconductor substrate having a dislocation density lower than or equal to 1×107 cm?2 with a chemical decomposition layer interposed therebetween, the chemical decomposition layer being chemically decomposed at least with either a gas or an electrolytic solution, and decomposing the chemical decomposition layer at least with either the gas or the electrolytic solution at least either during or after the step of growing the nitride semiconductor epitaxial layer, thereby separating the nitride semiconductor epitaxial layer from the nitride semiconductor substrate. A high-quality nitride semiconductor epitaxial layer suffering less damage when separated from the nitride semiconductor substrate is thereby formed.

Abstract: The present method of forming a nitride semiconductor epitaxial layer includes the steps of growing at least one layer of nitride semiconductor epitaxial layer on a nitride semiconductor substrate having a dislocation density lower than or equal to 1×107 cm?2 with a chemical decomposition layer interposed therebetween, the chemical decomposition layer being chemically decomposed at least with either a gas or an electrolytic solution, and decomposing the chemical decomposition layer at least with either the gas or the electrolytic solution at least either during or after the step of growing the nitride semiconductor epitaxial layer, thereby separating the nitride semiconductor epitaxial layer from the nitride semiconductor substrate. A high-quality nitride semiconductor epitaxial layer suffering less damage when separated from the nitride semiconductor substrate is thereby formed.

Abstract: Provided is a III nitride semiconductor electronic device having a structure capable of reducing leakage current. A laminate 11 includes a substrate 13 and a III nitride semiconductor epitaxial film 15. The substrate 13 is made of a III nitride semiconductor having a carrier concentration of more than 1×1018 cm?3. The epitaxial structure 15 includes a III nitride semiconductor epitaxial film 17. A first face 13a of the substrate 13 is inclined at an angle ? of more than 5 degrees with respect to an axis Cx extending in a direction of the c-axis. A normal vector VN and a c-axis vector VC make the angle ?. The III nitride semiconductor epitaxial film 17 includes first, second and third regions 17a, 17b and 17c arranged in order in a direction of a normal to the first face 13a. A dislocation density of the third region 17c is smaller than that of the first region 17a. A dislocation density of the second region 17b is smaller than that of the substrate 13.

Abstract: A method of fabricating a gallium nitride-based semiconductor electronic device is provided, the method preventing a reduction in adhesiveness between a gallium nitride-based semiconductor layer and a conductive substrate. A substrate 11 is prepared. The substrate 11 has a first surface 11a and a second surface 11b, the first surface 11a allowing a gallium nitride-based semiconductor to be deposited thereon. The substrate 11 includes a support 13 of a material different from the gallium nitride-based semiconductor. The support is exposed on the second surface 11b of the substrate 11. An array of grooves 15 is provided in the second surface 11b. A semiconductor region including at least one gallium nitride-based semiconductor layer is deposited on the first surface 11a of the substrate 11, and thereby an epitaxial substrate E is fabricated.

Abstract: In step S103, a gallium nitride semiconductor layer 13 is grown on an n-type GaN substrate 11. In step S104, a PL spectrum for the gallium nitride based semiconductor layer in a wavelength region including the yellow band of wavelength and the band edge wavelength of the gallium nitride based semiconductor is measured at room temperature. In step S106, a screened epitaxial substrate E1 is prepared through selection based on comparison of the photoluminescence spectrum intensity in the yellow band of wavelength and the band edge wavelength with a reference value. In step S107, an electrode 15 for an electron device is formed on the screened epitaxial substrate 13.

Abstract: There are provided a method of producing a group III-V compound semiconductor, a Schottky barrier diode, a light emitting diode, a laser diode and methods of fabricating the diodes, that can achieve a reduced n type carrier density. The method of producing a group III-V compound semiconductor is a method of producing the compound semiconductor by metal organic chemical vapor deposition employing a material containing a group III element. Initially the step of preparing a seed substrate is performed. Then the step of growing a group III-V compound semiconductor on the seed substrate is performed by employing as a group III element-containing material an organic metal containing at most 0.01 ppm of silicon, at most 10 ppm of oxygen and less than 0.04 ppm of germanium.