A silicon carbide crystal boule includes a flat surface, a truncated cone surface, and an annular curved surface. The annular curved surface connects the flat surface and the truncated cone surface. A width of the silicon carbide crystal boule gradually decreases from a first end of the truncated cone surface connecting the annular curved surface to a second end opposite to the first end.

A silicon carbide wafer having a seed end and a dome end opposite to the seed end. In the silicon carbide wafer, a basal plane dislocation (BPD) density detected by potassium hydroxide (KOH) etching is less than 550 pcs/cm.sup.2 at both the seed end and the dome end, and a basal plane dislocation (PL-BPD) density detected by photoluminescence is less than 2000 pcs/cm.sup.2 at both the seed end and the dome end.

A silicon carbide seed is provided, including a first seed layer and a second seed layer. The first seed layer includes a polycrystalline silicon carbide material. The second seed layer is directly attached to the first seed layer, where the second seed layer includes a single crystal silicon carbide material, and a thickness ratio (T2/T1) of a thickness T1 of the first seed layer to a thickness T2 of the second seed layer is in a range of 10% to 50%.

A semiconductor processing method includes the following steps. A semiconductor ingot is cut to obtain a semiconductor wafer, in which the semiconductor wafer includes a first side and a second side opposite to the first side. A double-sided grinding process is performed to simultaneously grind the first side and the second side of the semiconductor wafer using diamond grinding fluid. The diamond grinding fluid contains diamond particles with a median particle diameter of 0.1 m to 3 m.

The present application discloses a method and apparatus for synchronous growth of silicon carbide crystals in multiple crucibles comprising a chamber and an insulation layer assembly arranged close to inner walls of the chamber wherein the insulation layer assembly is used to divide the chamber into a plurality of independent growth cavities, and each of the growth cavities is provided with an independent growth assembly; wherein the independent growth assembly comprises a graphite crucible, a seed crystal tray arranged on the top of the graphite crucible and a drive assembly arranged at the bottom the crucible.

A method for growing crystals using PVT or PVD or CVD, includes: providing: a chamber for crystal growth, a crucible in the chamber including at least one deposition section with a seed crystal and a base material for crystal growth, at least one temperature monitoring device, a gas supply device and at least one fluid inlet and outlet, and a pressure monitoring device; evacuating the chamber using a pumping device; flushing the chamber with inert gas; heating the chamber to a growth temperature of 2000 to 2400 C. using at least one heating device; decreasing pressure to 0.1 to 100 mbar; supplying a dopant (during a growth process); regulating process parameters in the growth process; increasing chamber pressure at the growth process end; cooling down the chamber; wherein the heating of the chamber from an ambient temperature to the growth temperature occurs within 10 to 10000 minutes.

The invention provides a method of detecting crystallographic defects, comprising: sampling wafer of an ingot in complying with a predetermined wafer sampling frequency; identifying crystallographic defects of the wafer to show the crystallographic defects of the wafer; characterizing observation of the crystallographic defects of the wafer and extracting a value characterizing the crystallographic defects; through a result of characterizing the crystallographic defects, obtaining a radial distribution of density of the wafer and categorizing the crystallographic defects; and obtaining an isogram of the crystallographic defects of the wafer to show a crystallographic defect distribution of the whole ingot according to the value characterizing the crystallographic defects and categories of the crystallographic defects. It is no need to break the ingot to obtain the crystallographic defect distribution of the whole ingot, through which the technology for growing the ingot may be effectively adjusted to obtain the ingot with required characteristics of defect.

A bulk SiC single crystal is produced by sublimation growth. A stress measurement to detect initial internal mechanical seed stresses is carried out on a wafer-shaped single crystalline SiC seed crystal. The seed crystal is classified, according to the stress measurement, into a first class when the initial seed stresses are below a first stress boundary value, into a second class when the initial seed stresses lie between the first stress boundary value and a second stress boundary value, and into a third class when the initial seed stresses exceed the second stress boundary value. The actual sublimation growth for growing the bulk SiC single crystal is carried out with the SiC seed crystal only when it has been classified into the first or second class, and when it is classified into the second class, at least one stress-reducing measure is carried out.

There is a method for forming a semiconductor nanostructure on a substrate. The method includes placing a substrate and a semiconductor material in a pulsed laser deposition chamber; selecting parameters including a fluence of a laser beam, a pressure P inside the chamber, a temperature T of the substrate, a distance d between the semiconductor material and the substrate, and a gas molecule diameter a.sub.0 of a gas to be placed inside the chamber so that conditions for a Stranski-Krastanov nucleation are created; and applying the laser beam with the selected fluence to the semiconductor material to form a plume of the semiconductor material. The selected parameters determine the formation, from the plume, of (1) a nanolayer that covers the substrate, (2) a polycrystalline wetting layer over the nanolayer, and (3) a single-crystal nanofeature over the polycrystalline wetting layer, and the single-crystal nanofeature is grown free of any catalyst or seeding layer.

The present invention provides a multilayer seed which is designed such as to offer a virtually unstressed surface onto which a single-crystal can grow without the negative impact of the internal stress carried by monocrystalline seeds, in particular at the high temperatures conventionally used in sublimation processes. The multilayer seed for growing a single-crystal comprise at least two seed layers, wherein each of the at least two seed layers is a monocrystalline layer characterized by one or more parameters associated with a respective degree of internal stress. The one or more parameters are selected such that the at least two seed layers are adapted to counter-act the respective internal stresses from each other.