Provided is a semiconductor epitaxial wafer in which the concentration of hydrogen in a modifying layer can be maintained at a high level and the crystallinity of an epitaxial layer is excellent. A semiconductor epitaxial wafer has a semiconductor wafer, a modifying layer formed in a surface portion of the semiconductor wafer, which modifying layer has hydrogen contained as a solid solution in the semiconductor wafer, and an epitaxial layer formed on the modifying layer. The concentration profile of hydrogen in the modifying layer in the thickness direction from a surface of the epitaxial layer is a double peak concentration profile including a first peak shallower in the depth direction and a second peak deeper in the depth direction.

A method of manufacturing a nitride semiconductor light-emitting element includes: growing an n-side superlattice layer that includes InGaN layers and GaN layers; and, after the step of growing the n-side superlattice layer, growing a light-emitting layer. The step of growing the n-side superlattice layer comprises repeating a cycle n times (n is a number of repetition), the cycle including growing one InGaN layer and growing one GaN layer. In the step of growing the n-side superlattice layer, the step of growing one GaN layer in each cycle from a first cycle to an mth cycle is performed using carrier gas that contains N.sub.2 gas and does not contain H.sub.2 gas. The step of growing one GaN layer in each cycle from a (m+1)th cycle to an nth cycle is performed using gas containing H.sub.2 gas as the carrier gas.

It is an object of the present invention to provide a silicon carbide substrate having a low defect density that does not contaminate a process device and a silicon carbide semiconductor device including the silicon carbide substrate. A silicon carbide substrate according to the present invention is a silicon carbide substrate including: a substrate inner portion; and a substrate outer portion surrounding the substrate inner portion, wherein non-dopant metal impurity concentration of the substrate inner portion is 1×10.sup.16 cm.sup.−3 or more, and a region of the substrate outer portion at least on a surface side thereof is a substrate surface region in which the non-dopant metal impurity concentration is less than 1×10.sup.16 cm.sup.−3.

The composite defect includes an extended defect and a basal plane dislocation. The extended defect includes a first region extending in a <11-20> direction from an origin located at a boundary between the silicon carbide substrate and the silicon carbide epitaxial film, and a second region extending along a <1-100> direction. The first region has a width in the <1-100> direction that increases from the origin toward the second region. The basal plane dislocation includes a third region continuous to the origin and extending along the <1-100> direction, and a fourth region extending along a direction intersecting the <1-100> direction. When an area of the main surface is a first area, and an area of a quadrangle circumscribed around the composite defect is a second area, a value obtained by dividing the second area by the first area is not more than 0.001.

A circuit assembly is provided and includes a printed circuit board (PCB) having a circuit element region and defining a trench surrounding an entirety of the circuit element region, a circuit element disposed within the circuit element region of the PCB; and a Faraday wall. The Faraday wall includes a solid, unitary body having a same shape as the trench. The Faraday wall is disposed within the trench to surround an entirety of the circuit element.

A method for producing a GaN crystal that includes: (i) a seed crystal preparation step of preparing a GaN seed crystal having one or more facets selected from a {10-10} facet and a {10-1-1} facet; and (ii) a growth step of growing GaN from vapor phase on a surface comprising the one or more facets of the GaN seed crystal using GaCl.sub.3 and NH.sub.3 as raw materials.

It is provided a layer of a nitride of a group 13 element having a first main face and second main face. The layer of the nitride of the group 13 element includes a first void-depleted layer provided on the side of the first main face, a second void-depleted layer provided on the side of the second main face, and the void-distributed layer provided between the first void-depleted layer and second void-depleted layer.

A valve device includes a valve body that defines flow paths, a diaphragm provided so as to be capable of opening and closing the flow paths, an operation member provided so as to be capable of moving in opening and closing directions that open and close the flow paths by operating the diaphragm, a main actuator that applies a driving force corresponding to an operating pressure applied in the opening direction or the closing direction of the opening and closing directions with respect to the operation member, a switching mechanism capable of selectively switching a position of the operation member that regulates a degree of opening of the flow paths between a first open position and a second open position in accordance with a magnitude of the operating pressure, and regulating mechanisms capable of independently regulating the first open position and the second open position.

Diffusion of a group III material into an Si substrate is suppressed during the time when a group III nitride semiconductor layer is grown on the Si substrate, with an AlN buffer layer being interposed therebetween. A method for manufacturing a group III nitride semiconductor substrate comprises: a step for growing a first AlN buffer layer on an Si substrate; a step for growing a second AlN buffer layer on the first AlN buffer layer at a temperature higher than a growth temperature of the first AlN buffer layer; and a step for growing a group III nitride semiconductor layer on the second AlN buffer layer. The growth temperature of the first AlN buffer layer is 400-600° C.

In a silicon carbide stacked substrate, the efficiency of converting the basal plane dislocation (BPD) which is a fault to deteriorate the current-carrying reliability into a threading edge dislocation (TED) which is a harmless fault is improved, thereby improving the reliability of the silicon carbide stacked substrate. As means therefor, in a silicon carbide stacked substrate including a SiC substrate and a buffer layer and a drift layer which are epitaxial layers sequentially formed on the SiC substrate, a semiconductor layer having an impurity concentration lower than those of the SiC substrate and the buffer layer and higher than that of the drift layer is formed between the SiC substrate and the buffer layer so as to be in contact with an upper surface of the SiC substrate.