A nitride semiconductor template includes a heterogeneous substrate, a first nitride semiconductor layer that is formed on one surface of the heterogeneous substrate, includes a nitride semiconductor and has an in-plane thickness variation of not more than 4.0%, and a second nitride semiconductor layer that is formed on an annular region including an outer periphery of an other surface of the heterogeneous substrate, includes the nitride semiconductor and has a thickness of not less than 1 μm.

A method of fabricating a semiconductor device includes implanting dopants into a silicon substrate, and performing a thermal anneal process that activates the implanted dopants. In response to activating the implanted dopants, a layer of ultra-thin single-crystal silicon is formed in a portion of the silicon substrate. The method further includes performing a heteroepitaxy process to grow a semiconductor material from the layer of ultra-thin single-crystal silicon.

A semiconductor wafer of single-crystal silicon has an oxygen concentration per new ASTM of not less than 5.0×10.sup.17 atoms/cm.sup.3 and not more than 6.5×10.sup.17 atoms/cm.sup.3; a nitrogen concentration per new ASTM of not less than 1.0×10.sup.13 atoms/cm.sup.3 and not more than 1.0×10.sup.14 atoms/cm.sup.3; a front side having a silicon epitaxial layer wherein the semiconductor wafer has BMDs whose mean size is not more than 10 nm determined by transmission electron microscopy and whose mean density adjacent to the epitaxial layer is not less than 1.0×10.sup.11 cm.sup.−3, determined by reactive ion etching after having subjected the wafer covered with the epitaxial layer to a heat treatment at a temperature of 780° C. for a period of 3 h and to a heat treatment at a temperature of 600° C. for a period of 10 h.

A method for manufacturing an epitaxial wafer by forming a single crystal silicon layer on a wafer containing a group IV element including silicon, the method including the steps of: removing a natural oxide film on a surface of the wafer containing the group IV element including silicon in an atmosphere containing hydrogen; forming an oxygen atomic layer by oxidizing the wafer after removing the natural oxide film; and forming a single crystal silicon by epitaxial growth on the surface of the wafer after forming the oxygen atomic layer, where a planar density of oxygen in the oxygen atomic layer is set to 4×10.sup.14 atoms/cm.sup.2 or less. A method for manufacturing an epitaxial wafer having an epitaxial layer of good-quality single crystal silicon while also allowing the introduction of an oxygen atomic layer in an epitaxial layer stably and simply.

There is provided a technique that includes filling a concave portion formed on a surface of a substrate with a first film and a second film by performing: (a) forming the first film having a hollow portion using a first precursor so as to fill the concave portion formed on the surface of the substrate; (b) etching a portion of the first film which makes contact with the hollow portion, using an etching agent; and (c) forming the second film on the first film of which the portion is etched, using a second precursor, wherein (b) includes performing, a predetermined number of times: (b-1) modifying a portion of the first film using a modifying agent; and (b-2) selectively etching the modified portion of the first film using the etching agent.

A two-dimensional semiconductor transistor includes a gate electrode, a gate insulating layer disposed on the gate electrode, an organic dopant layer disposed on the gate insulating layer and comprising an organic material including electrons, a two-dimensional semiconductor layer disposed on the organic dopant layer, a source electrode disposed on the two-dimensional semiconductor layer, and a drain electrode disposed on the two-dimensional semiconductor layer and spaced apart from the source electrode. A hysteresis of the two-dimensional semiconductor transistor is reduced due to the two-dimensional semiconductor transistor including the organic dopant layer.

Heterostructures include a layer of a two-dimensional material placed on a multiferroic layer. An ordered array of differing polarization domains in the multiferroic layer produces corresponding domains having differing properties in the two-dimensional material. When the multiferroic layer is ferroelectric, the ferroelectric polarization domains in the layer produce local electric fields that penetrate the two-dimensional material. The local electric fields modulate the charge carriers and carrier density on a nanometer length scale, resulting in the formation of lateral p-n or p-i-n junctions, and variations thereof appropriate for device functions.

A method of manufacturing nitride semiconductor substrate, comprising: providing silicon-on-insulator substrate which comprises an underlying silicon layer, a buried silicon dioxide layer and a top silicon layer; forming a first nitride semiconductor layer on the top silicon layer; forming, in the first nitride semiconductor layer, a plurality of notches which expose the top silicon layer; removing the top silicon layer and forming a plurality of protrusions and a plurality of recesses on an upper surface of the buried silicon dioxide layer, wherein each of the plurality of protrusions is in contact with the first nitride semiconductor layer, and there is a gap between each of the plurality of recesses and the first nitride semiconductor layer; and epitaxially growing a second nitride semiconductor layer on the first nitride semiconductor layer, such that the first nitride semiconductor layer and the second nitride semiconductor layer form a nitride semiconductor substrate.

An epitaxial wafer that includes a silicon wafer and an epitaxial layer on the silicon wafer. The silicon wafer contains hydrogen that has a concentration profile including a first peak and a second peak. A hydrogen peak concentration of the first peak and a hydrogen peak concentration of the second peak are each not less than 1×10.sup.17 atoms/cm.sup.3.

A process for manufacturing a composite structure comprises: a) providing an initial substrate made of monocrystalline silicon carbide, b) epitaxially growing a monocrystalline silicon carbide donor layer on the initial substrate to form a donor substrate 111, c) implanting ions into the donor layer to form a buried brittle plane defining the the donor layer, d) depositing, using liquid injection-chemical vapor deposition at a temperature below 1000° C., a carrier layer on the donor layer, the carrier layer comprising an at least partially amorphous SiC matrix, e) separating the donor substrate along the brittle plane to form an intermediate composite structure comprising the donor layer on the carrier layer f) heat treating the intermediate composite structure at a temperature of between 1000° C. and 1800° C. to crystallize the carrier layer and form the polycrystalline carrier substrate, and g) applying mechanical and/or chemical treatment(s) of the composite structure.