A non-polar blue light LED epitaxial wafer based on an LAO substrate comprises the LAO substrate, and a buffer layer, a first non-doped layer, a first doped layer, a quantum well layer, an electron barrier layer and a second doped layer that are sequentially arranged on the LAO substrate. A preparation method of the non-polar blue light LED epitaxial wafer includes: a) adopting the LAO substrate, selecting a crystal orientation, and cleaning a surface of the LAO substrate; b) annealing the LAO substrate, and forming an AlN seed crystal layer on the surface of the LAO substrate; and c) sequentially forming a non-polar m face GaN buffer layer, a non-polar non-doped u-GaN layer, a non-polar n-type doped GaN film, a non-polar InGaN/GaN quantum well, a non-polar m face AlGaN electron barrier layer and a non-polar p-type doped GaN film on the LAO substrate by adopting metal organic chemical vapor deposition.

A non-polar blue light LED epitaxial wafer based on an LAO substrate comprises the LAO substrate, and a buffer layer, a first non-doped layer, a first doped layer, a quantum well layer, an electron barrier layer and a second doped layer that are sequentially arranged on the LAO substrate. A preparation method of the non-polar blue light LED epitaxial wafer includes: a) adopting the LAO substrate, selecting a crystal orientation, and cleaning a surface of the LAO substrate; b) annealing the LAO substrate, and forming an AlN seed crystal layer on the surface of the LAO substrate; and c) sequentially forming a non-polar m face GaN buffer layer, a non-polar non-doped u-GaN layer, a non-polar n-type doped GaN film, a non-polar InGaN/GaN quantum well, a non-polar m face AlGaN electron barrier layer and a non-polar p-type doped GaN film on the LAO substrate by adopting metal organic chemical vapor deposition.

The device forming a crucible for fabrication of crystalline material by directional solidification comprises a bottom and at least one side wall. The bottom presents a first portion having a first thermal resistance and a second portion having a second thermal resistance that is lower than the first thermal resistance. The second portion is designed to receive a seed for fabrication of the crystalline material. The bottom and side wall are at least partially formed by a tightly sealed part including at least one indentation participating in defining said first and second portions. The first portion is covered by a first anti-adherent layer having an additional first thermal resistance. The second portion may be covered by a second anti-adherent layer having an additional second thermal resistance that is lower than the first thermal resistance.

The device forming a crucible for fabrication of crystalline material by directional solidification comprises a bottom and at least one side wall. The bottom presents a first portion having a first thermal resistance and a second portion having a second thermal resistance that is lower than the first thermal resistance. The second portion is designed to receive a seed for fabrication of the crystalline material. The bottom and side wall are at least partially formed by a tightly sealed part including at least one indentation participating in defining said first and second portions. The first portion is covered by a first anti-adherent layer having an additional first thermal resistance. The second portion may be covered by a second anti-adherent layer having an additional second thermal resistance that is lower than the first thermal resistance.

Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm.sup.?2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm.sup.?2 or less, or 100 cm.sup.?2 or less, or 10 cm.sup.?2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm.sup.?2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm.sup.?2 or less, or 100 cm.sup.?2 or less, or 10 cm.sup.?2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

The present invention relates to a substrate-triggered single crystal superalloy directional solidification process, including: (1) preparing a single crystal substrate material having crystallographic characteristics that match crystallographic characteristics of the single crystal superalloy; (2) fabricating a single crystal substrate chilling plate using the obtained single crystal substrate material; and (3) applying the obtained single crystal substrate chilling plate in a directional solidification apparatus, and then preparing a single crystal alloy product by performing superalloy melting and directional solidification. Compared with grain selector method and seeding with grain selector method, in addition to control the crystallographic orientation of the single crystal superalloy precisely, the present invention could reduce the height of block and the whole mold through canceling the spiral grain selector, significantly improve the axial heat dissipation and temperature gradient at the solid-liquid interface, and then reduce the occurrence of freckles and stray grains near platform.

The present invention relates to a substrate-triggered single crystal superalloy directional solidification process, including: (1) preparing a single crystal substrate material having crystallographic characteristics that match crystallographic characteristics of the single crystal superalloy; (2) fabricating a single crystal substrate chilling plate using the obtained single crystal substrate material; and (3) applying the obtained single crystal substrate chilling plate in a directional solidification apparatus, and then preparing a single crystal alloy product by performing superalloy melting and directional solidification. Compared with grain selector method and seeding with grain selector method, in addition to control the crystallographic orientation of the single crystal superalloy precisely, the present invention could reduce the height of block and the whole mold through canceling the spiral grain selector, significantly improve the axial heat dissipation and temperature gradient at the solid-liquid interface, and then reduce the occurrence of freckles and stray grains near platform.

The present invention relates to a method for producing a silicon ingot from a silicon melt by directional solidification, wherein the growth of the silicon ingot is initiated by bringing the silicon melt into contact with at least one silicon seed, characterised in that at least the surface of the seed brought into contact with the silicon melt is oxidised.

A silicon member for a semiconductor apparatus is provided. The silicon member has an equivalent performance to one fabricated from a single-crystalline silicon even though it is fabricated from a unidirectionally solidified silicon. In addition, it can be applied for producing a relatively large-sized part. The silicon member is fabricated by sawing a columnar crystal silicon ingot obtained by growing a single-crystal from each of seed crystals by placing the seed crystals that are made of a single-crystalline silicon plate on a bottom part of a crucible and unidirectionally solidifying a molten silicon in the crucible.