72results about How to "Improve epitaxy quality" patented technology

The invention discloses a preparation method of a low stress state composite substrate for GaN growth. The preparation method comprises that a GaN monocrystal epitaxial layer is prepared on a sapphire substrate; a stress compensation layer is deposited at the back side of a thermally and electrically conductive transfer substrate of high welding point; bonding dielectric layers of high welding point are prepared at the surfaces of a GaN epitaxial wafer and the transfer substrate respectively; the GaN epitaxial wafer is bonded to the thermally and electrically conductive substrate by the high-temperature diffusion bonding technology; and the composite substrate with high temperature stability and low stress state for GaN growth is obtained. According to the composite substrate of the invention, homoepitaxy can be realized and a vertical structural device can be directly prepared as a traditional composite substrate, the low stress state and high-temperature stability can be also realized, and the quality of subsequent GaN epitaxial growth and chip preparation can be effectively improved.

A multiple quantum well structure includes a plurality of well-barrier sets arranged along a direction. Each of the well-barrier sets includes a barrier layer, at least one intermediate level layer, and a well layer. A bandgap of the barrier layer is greater than an average bandgap of the intermediate level layer, and the average bandgap of the intermediate level layer is greater than a bandgap of the well layer. The barrier layers, the intermediate level layers, and the well layers of the well-barrier sets are stacked by turns. Thicknesses of at least parts of the well layers in the direction gradually decrease along the direction, and thicknesses of at least parts of the intermediate level layers in the direction gradually increase along the direction. A method for manufacturing a multiple quantum well structure is also provided.

The invention relates to a porous-DBR-based InGaN-based resonant cavity enhanced detector chip comprising a substrate, a buffer layer formed on the substrate, a bottom porous DBR layer formed on the buffer layer, an n type GaN layer formed on the bottom porous DBR layer, an active region formed on the n type GaN layer, a p type GaN layer formed in the active region, a side wall passivation layer, a transparent conductive layer, an n electrode, a p electrode, and a top dielectric DBR layer. The one side of the n type GaN layer is formed downwardly to form a table board and a protrusion is formed at the other side of the n type GaN layer. The side wall passivation layer is formed at the upper surface of the p type GaN layer and the side walls of the protruding n type GaN layer, the active region, and the p type GaN layer; and a window is formed in the middle of the side wall passivation layer formed at the upper surface of the p type GaN layer. The transparent conductive layer is formed at the upper surfaces of the side wall passivation layer and the p type GaN layer at the window. The n electrode is formed on the table board of the n type GaN layer. The p electrode is manufactured around the upper surface of the side wall passivation layer. And the top dielectric DBR layer is formed on the transparent conductive layer and the p electrode.

A gallium nitride-based light emitting device with a roughened surface is described. The light emitting device comprises a substrate, a buffer layer grown on the substrate, an n-type III-nitride semiconductor layer grown on the buffer layer, a III-nitride semiconductor active layer grown on the n-type III-nitride semiconductor layer, a first p-type III-nitride semiconductor layer grown on the III-nitride semiconductor active layer, a heavily doped p-type III semiconductor layer grown on the first p-type III-nitride semiconductor, and a roughened second p-type III-nitride semiconductor layer grown on the heavily doped p-type III semiconductor layer.

The invention relates to a method for preparing III-V compound semiconductor nanotube structure material by GSMBE, which comprises the following steps: pretreating a substrate in a GSMBE system; using As2 obtained by arsine decomposition as an As source, adjusting the pressure PV of AsH3 in an air source furnace to 450 to 700 Torr, and controlling the intensity of molecular flows; transferring the substrate to a GSMBE growth chamber for epitaxial growth; and making patterns by using a semiconductor etching process, and making the III-V compound semiconductor nanotube structure material after etching. The III-V compound semiconductor material system is highly selective, convenient in resource as well as capable of doping nanotube interior and exterior wall materials. The preparation method is simple in operation, low in cost and suitable for large-scale production.

The invention discloses ABO3/MgO/GaN heterojunction structure and a preparation method thereof, and relates to the field of microelectronic material. The ABO3/MgO/GaN heterojunction structure comprises a substrate and ABO3, wherein, an MgO nano buffer layer film is arranged between the substrate and the ABO3, the substrate is GaN epitaxial slice, and the ABO3 is oxide film material with calcium-state structure. The MgO film has good thermal stability and can be combined with oxygen stably, so as to be an effective blocking layer for preventing oxygen atoms from spreading towards the semiconductor substrate; meanwhile, MgO has the cubic symmetry crystalline structure with the crystallographic lattice constant approaching to most of ferroelectric oxide; the MgO film with nano thickness leads a ferroelectric film with the ABO3 structure which grows subsequently can grow on the GaN in an oriented way. The ABO3/MgO/GaN heterojunction structure prepared by the invention has clear interlayer interfaces, thus providing a feasible material design and growing method for realizing oxide/semiconductor integrated devices.

The invention relates to a method for epitaxial growth of a gallium nitride (GaN) thin film on a Si substrate, the crack growth of GaN epitaxial thin films is limited, the surface topography is uniform, the process is relatively easy, and the method is easy to realize. According to the technical scheme, the method includes the steps that a metal-organic chemical vapor deposition (MOCVD) system isadopted for epitaxial growth and the epitaxial growth of the GaN thin film is conducted on the Si substrate. The method is characterized in that the epitaxial structure of the GaN thin film sequentially comprises the Si substrate, a pre-buried aluminum layer, a low temperature aluminum nitride (AlN) buffer layer, a high temperature aluminum nitride (AlN) buffer layer, a gallium nitride aluminum (AlxGal-xN) layer and the GaN thin film layer, wherein the low temperature AlN buffer layer is a low temperature AlN three-dimensional nucleating layer, the high temperature AlN buffer layer is a high temperature AlN three-dimensional nucleating layer, the AlxGal-xN layer is an AlxGal-xN stress relief layer, and the GaN thin film layer is a final growth layer.

The invention relates to a graphical silicon carbide (SiC) substrate. The surface of the graphical SiC substrate comprises periodized protrusions or concave images which are formed by means of plasma etching or wet etching, wherein the periodized protrusions or the concave images are any one of multilateral cones, multilateral cylinders, multi-rowed frustums, trapezoid multilateral frustums, trapezoid round pedestals, hemispheres or spherical crowns. Periodic images are combination of any two or more than two of the multilateral cones, the multilateral cylinders, the multi-rowed frustums, the trapezoid multilateral frustums, the trapezoid round pedestals, the hemispheres or the spherical crowns. The graphical SiC substrate can improve epitaxy quality of heteroepitaxy of gallium nitride (GaN) and homoepitaxy of 3C-SiC which take SiC as the substrate, and improves performance and stability of elements prepared by epitaxial wafers.

The present invention relates to an ultraviolet light-emitting diode (LED), which includes a gradual superlattice layer. The gradual superlattice layer comprises a first superlattice layer and a second superlattice layer. The first superlattice layer includes a multi-layer structure having repetitive stacks of a unit formed by a first layer and a second layer. The second superlattice layer includes a multi-layer structure having repetitive stacks of a unit formed by a third layer and a fourth layer. The concentrations of aluminum in the first, second, third, and fourth layers decrease sequentially. By disposing the gradual superlattice layer, the quality of the epitaxial structure may be improved apparently.

A semiconductor light-emitting device and a manufacturing method thereof are provided, wherein the semiconductor light-emitting device includes a substrate, a first type doped semiconductor layer, a light-emitting layer, a second type doped semiconductor layer and an optical micro-structure layer. The first type doped semiconductor layer is disposed on the substrate and includes a base portion and a mesa portion. The base portion has a top surface, and the mesa portion is disposed on the top surface of the base portion. The light-emitting layer is disposed on the first type doped semiconductor layer. The second type doped semiconductor layer is disposed on the light-emitting layer. The optical micro-structure layer is embedded in the first type doped semiconductor layer.

A semiconductor substrate and a manufacturing method thereof are provided. The semiconductor substrate has an epitaxy region located at a central portion of a main plane of the semiconductor substrate, a periphery region surrounding the epitaxy region and an injured region distributed inside the periphery region.

The present invention provides a light-emitting semiconductor device, which comprises a substrate having a surface formed with a plane and a plurality of protrusions out of the plane. The plane is on a crystalline orientation. The protrusion is provided with an outer surface consisting of a plurality of sidewall surfaces. The sidewall surfaces are substantially not on the crystalline orientation. The protrusion is formed with an outline edge extended from the bottom to the top of the protrusion from a side view. The outline edge comprises at least one turning point. A first conductive type semiconductor layer is above the surface of the substrate, an active layer is above the first conductive type semiconductor layer, and a second conductive type semiconductor layer is above the active layer.

The invention discloses a patterned substrate of an LED chip and an LED chip. Patterns of the substrate consist of a plurality of identically-shaped spherical caps arranged on the surface of the substrate, the height h of each spherical cap is 75-85 percent of the radius R of the sphere corresponding to the spherical cap, and the distance d between the edges of the adjacent spherical caps is 30-50 percent of the radius r of the bottom surface of the spherical caps. Compared with the prior art, the patterned substrate has better light extraction efficiency than a substrate with hemispherical patterns with the same bottom surface radius, is simpler in actual processing and facilitates popularized application.

The invention discloses a semiconductor light-emitting device and a method of fabricating the same. The semiconductor light-emitting device according to the invention includes a substrate, a buffer layer, a multi-layer structure, and an ohmic electrode structure. The buffer layer is selectively formed on an upper surface of the substrate such that the upper surface of the substrate is partially exposed. The multi-layer structure is formed to overlay the buffer layer and the exposed upper surface of the substrate. The multi-layer structure includes a light-emitting region. The buffer layer assists a bottom-most layer of the multi-layer structure in lateral and vertical epitaxial growth. The ohmic electrode structure is formed on the multi-layer structure.

The invention discloses a manufacturing method of an embedded epitaxial layer. The method comprises the steps of 1, forming a U-shaped groove in a silicon substrate by adopting a dry etching process;and 2, filling an embedded epitaxial layer in the groove, wherein the step 2 comprises the sub-steps of 21, carrying out epitaxial growth to form a buffer layer; 22, carrying out epitaxial growth to form a main body layer, and forming particle defects in the growth process of the main body layer; 23, introducing an etching gas into the same epitaxial growth cavity to perform back etching so as toremove particle defects; and 24, carrying out epitaxial growth to form a cap layer. According to the invention, the particle defects generated in the epitaxial growth process of the embedded epitaxiallayer can be eliminated, so that the yield of products can be improved.

The invention discloses a light-emitting diode (LED) structure which comprises a substrate, a first doped semiconductor layer, a first electrode, a light-emitting layer, a second doped semiconductor layer and a second electrode, wherein the substrate is provided with a surface and a plurality of cylindrical photon crystals positioned on the surface; the first doped semiconductor layer is arranged on the substrate to cover the photon crystals; the light-emitting layer, the second doped semiconductor layer and the second electrode are sequentially arranged on part of the first doped semiconductor layer; and the first electrode is arranged on part of the first doped semiconductor layer on which the light-emitting layer is not covered. Because the substrate provided with the photon crystals can improve the epitaxial quality of the first doped semiconductor layer and increase the light energy of the forward ejected LED structure, the light-emitting efficiency of the LED structure can be effectively improved.