33results about How to "Reduce surface defect density" patented technology

A film 3 of a nitride of a group 13 element is grown on a seed crystal substrate 11 by flux process from a melt containing a flux and the group 13 element under nitrogen containing atmosphere. The film 3 of the nitride of the group 13 element includes an inclusion distributed layer 3a in a region distant from an interface 11a of the film 3 of the nitride of the group 13 element on the side of the seed crystal substrate 11 and containing inclusions derived from components of the melt, and an inclusion depleted layer 3b, with the inclusion depleted. provided on the layer 3a. Laser light A is irradiated from the side of the back face 1b of the seed crystal substrate 11 to peel the single crystal 3 of the nitride of the group 13 element from the seed crystal substrate 11 by laser lift-off method.

A film 3 of a nitride of a group 13 element is grown on a seed crystal substrate 11 by flux process from a melt containing a flux and a group 13 element under nitrogen containing atmosphere. The film 3 of a nitride of a group 13 element includes an inclusion distributed layer 3a in a region distant from an interface of the film of a nitride of group 13 element on the side of the seed crystal substrate 11 and containing inclusions derived from components of the melt, and an inclusion depleted layer 3b, with the inclusion depleted. provided on the layer 3a.

The invention provides methods which can be applied during the epitaxial growth of two or more layers of Group III-nitride semiconductor materials so that the qualities of successive layer are successively improved. In preferred embodiments, surface defects interact with a protective layer of a protective material to form amorphous complex regions capable of preventing the further propagation of defects and dislocations. The invention also includes semiconductor structures fabricated by these methods.

The invention mainly belongs to the field of photoelectrochemistry water-splitting for hydrogen production and particularly relates to a vanadium-doped ZnO nanorod array photo-anode, a preparation method of the vanadium-doped ZnO nanorod array photo-anode and an application of the vanadium-doped ZnO nanorod array photo-anode in photoelectrochemistry water-splitting for hydrogen production. The method comprises the steps of preparing a ZnO seed crystal solution, a vanadium-doped solution and a growth solution correspondingly; conducting spin-coating on conducting glass with the ZnO seed crystal solution and obtaining the conducting glass with the surface covered with a ZnO seed crystal layer after spin-coating and annealing; pulling the conducting glass with the surface covered with the ZnO seed crystal layer into a mixed solution of the vanadium-doped solution and the growth solution for a hydrothermal reaction, washing the conducting glass with deionized water after completion of the reaction, conducting annealing in a muffle furnace and then obtaining an vanadium-doped ZnO nanorod array. By adopting the vanadium-doped ZnO nanorod array photo-anode provided by the invention, the carrier life is prolonged, combination of electron holes is reduced, and the photoelectrochemistry water-splitting performance is improved.

The invention discloses a preparation method of a (211) preferred orientation Mo film. The preparation method comprises the steps of: (1) cleaning a substrate, ultrasonically cleaning the substrate in acetone, ethanol and deionized water for 10 minutes respectively, and putting the substrate into a sputtering vacuum chamber after drying by nitrogen; (2) sputtering the Mo film, installing a high-purity Mo target on a magnetron sputtering target gun, adjusting a distance from the magnetron sputtering target gun to the substrate to be 50mm after purity achieves 99.99%, and vacuumizing a background in vacuum to be less than 3.0*10<-4>Pa, leading 99.995% of high-purity argon, adjusting sputtering work pressure to 0.15Pa and sputtering power to 5W / cm<2>, pre-sputtering the target for 10 minutes to remove surface contaminants after glow is stabilized, then beginning to deposit the film, and stopping after depositing for 20-40 minutes to obtain the Mo film with (211) preferred orientation. The film is high in crystal quality, even in surface appearance, low in resistivity and suitable for being used as a back electrode layer of a copper indium gallium diselenide film battery.

To provide silicon carbide epitaxial wafer in which occurrence of giant step bunchings (GSBs) caused by basal plane dislocations (BPDs) that occur during hydrogen etching is suppressed on low off-angle silicon carbide substrate to decrease surface defect density of epitaxially grown layer to allow formation of silicon carbide semiconductor device having high reliability, method for manufacturing the wafer, and apparatus for manufacturing the wafer, and silicon carbide semiconductor device having the wafer.A silicon carbide epitaxial wafer of the present invention is such that epitaxially grown layer is disposed on silicon carbide substrate which has α-type crystal structure and in which (0001) Si face is tilted at greater than 0° and less than 5°, wherein surface defect density of the epitaxially grown layer based on giant step bunching caused by basal plane dislocation on substrate surface of the silicon carbide substrate is ≦20 / cm2.

The invention provides a preparation method of an N-type low-defect silicon carbide epitaxial wafer. The method comprises the steps of preparation of a substrate, online substrate etching, growth of a buffer layer and growth of an epitaxial layer, wherein growth of the epitaxial layer includes growth, etching, blowing and re-growth. The method can be used to effectively reduce the dislocation density of the base, reduce deposit in the cavity, reduce the defect density of the surface of the silicon carbide epitaxial wafer, improve the quality of a silicon carbide epitaxial material, and is wide in application range, low in processing cost and suitable for industrial production.