The present disclosure falls into the field of optoelectronics, particularly, includes the design, epitaxial growth, fabrication, and characterization of Laser Diodes (LDs) operating in the ultraviolet (UV) to infrared (IR) spectral regime on patterned substrates (PSs) made with (formed on) low cost, large size Si, or GaN on sapphire, GaN, and other wafers. We disclose three types of PSs, which can be universal substrates, allowing any materials (III-Vs, II-VIs, etc.) grown on top of it with low defect and/or dislocation density.

A group-III-nitride structure and a manufacturing method thereof are provided. In the manufacturing method, a first mask layer is first formed on a substrate; an uncoalesced second group-III-nitride epitaxial layer is formed by performing a first epitaxial growth with the first mask layer as a mask; and a second mask layer is formed at least on the second group-III-nitride epitaxial layer; a third group-III-nitride epitaxial layer is laterally grown and formed by performing a second epitaxial growth on the second group-III-nitride epitaxial layer with the second mask layer as a mask, where the second group-III-nitride epitaxial layer is coalesced by the third group-III-nitride epitaxial layer; a fourth group-III-nitride epitaxial layer is formed by performing a third epitaxial growth on the third group-III-nitride epitaxial layer.

A semiconductor device includes a substrate, a nucleation layer, a buffer layer, first and second nitride-based semiconductor layers, a pair of S/D electrodes, and a gate electrode. The nucleation layer is disposed on the substrate. The buffer layer includes a III-V compound which includes a first element. The buffer layer is disposed on the nucleation layer. The buffer layer has a variable concentration of the first element that incrementally increases and then decrementally decreases as a function of a distance within a thickness of the buffer layer. The first nitride-based semiconductor layer is disposed on the buffer layer. The second nitride-based semiconductor layer is disposed on the first nitride-based semiconductor layer and has a bandgap greater than a bandgap of the first nitride-based semiconductor layer. The S/D electrodes and a gate electrode are disposed over the second nitride-based semiconductor layer.

A surface-emitting laser element includes: a first guide layer including a photonic crystal layer that is formed on a c plane of a group-3 nitride semiconductor and includes air holes arranged with two-dimensional periodicity in a plane parallel to the photonic crystal layer, and an embedding layer that is formed on the photonic crystal layer and closes the air holes; an active layer formed on the first guide layer; and a second guide layer formed on the active layer, wherein an air hole set including at least a main air hole and a sub-air hole smaller in size than the main air hole is arranged at each square lattice point in the plane parallel to the photonic crystal layer, and wherein the main air hole has a regular-hexagonal prism shape, a long-hexagonal prism shape, or an elliptic cylindrical shape with a major axis parallel to a <11-20> axis.

A crystal substrate 1 includes an underlying layer 2 and a thick film 3. The underlying layer 2 is composed of a crystal of a nitride of a group 13 element and includes a first main face 2a and a second main face 2b. The thick film 3 is composed of a crystal of a nitride of a group 13 element and provided over the first main face of the underlying layer. The underlying layer 2 includes a low carrier concentration region 5 and a high carrier concentration region 4 both extending between the first main face 2a and the second main face 2b.

A method for manufacturing a compound semiconductor substrate comprises: a step to form an SiC (silicon carbide) layer on a Si (silicon) substrate, a step to form a LT (Low Temperature)-AlN (aluminum nitride) layer with a thickness of 12 nanometers or more and 100 nanometers or less on the SiC layer at 700 degrees Celsius or more and 1000 degrees Celsius or less, a step to form a HT (High Temperature)-AlN layer on the LT-AlN layer at a temperature higher than the temperature at which the LT-AlN layer was formed, a step to form an Al (aluminum) nitride semiconductor layer on the HT-AlN layer, a step to form a GaN (gallium nitride) layer on the Al nitride semiconductor layer, and a step to form an Al nitride semiconductor layer on the GaN layer.

Provided is a semiconductor substrate with a balance stress. The semiconductor substrate includes a ceramics base, a nucleation layer and a first buffer layer doped with a first dopant. The ceramics base has an off-cut angle other than 0 degree. The nucleation layer is disposed on the ceramics base. The first buffer layer is disposed on the nucleation layer. The first dopant includes C, Fe or a combination thereof. The first buffer layer provides compressive stress to the ceramic base. The concentration of the first dopant in the first buffer layer is increased away from the ceramics base. The curvature of the semiconductor substrate is between 16 km.sup.−1 and −16 km.sup.−1.

An epitaxial structure of a GaN-based radio frequency device based on a Si substrate and a manufacturing method thereof are provided. The epitaxial structure is composed of a Si substrate (1), an AlN nucleation layer (2), AlGaN buffer layers (3, 4, 5), a GaN:Fe/GaN high-resistance layer (6), a GaN superlattice layer (7), a GaN channel layer (8), an AlGaN barrier layer (9) and a GaN cap layer (10) which are stacked in turn from bottom to top, wherein the GaN:Fe/GaN high-resistance layer (6) is composed of an intentional Fe-doped GaN layer and an unintentional doped GaN layer which are alternately connected; the GaN superlattice layer (7) is composed of a low-pressure/low V/III ratio GaN layer and a high-pressure/high V/III ratio GaN layer which are periodically and alternately connected.

A composite substrate is provided in some embodiments of the present disclosure, which includes a substrate, an insulation layer, a first silicon-containing layer and a first epitaxial layer. The insulation layer is disposed on the substrate. The first silicon-containing layer is disposed on the insulation layer, in which the first silicon-containing layer includes a plurality of group V atoms. The first epitaxial layer is disposed on the first silicon-containing layer, in which the first epitaxial layer includes a plurality of group III atoms. A distribution concentration of the group V atoms in the first silicon-containing layer increases as getting closer to the first epitaxial layer, and a distribution concentration of the group III atoms in the first epitaxial layer increases as getting closer to the first silicon-containing layer. A method of manufacturing a composite substrate is also provided in some embodiments of the present disclosure.

A buffer layer on a silicon carbide substrate and a method of forming the same are disclosed. The buffer layer includes at least two layers of silicon carbide films, in which at least each lower one is doped at a top surface thereof with predetermined ions. As a result, at the top surface of the silicon carbide film, a barrier with different parameter is formed, which can block dislocation defects that have spread into the silicon carbide film from further upward propagation in the silicon carbide film.