Abstract:
A process for the rapid synthesis of metal oxide nanoparticles at low temperatures and methods which facilitate the fabrication of long metal oxide nanowires. The method is based on treatment of metals with oxygen plasma. Using oxygen plasma at low temperatures allows for rapid growth unlike other synthesis methods where nanomaterials take a long time to grow. Density of neutral oxygen atoms in plasma is a controlling factor for the yield of nanowires. The oxygen atom density window differs for different materials. By selecting the optimal oxygen atom density for various materials the yield can be maximized for nanowire synthesis of the metal.
Abstract:
A laser mask and method of crystallization using the same that can produce a polycrystalline silicon thin film having uniform crystallization characteristics. According to the present invention, a method of crystallization using a laser mask having a reference pattern in a first block and the reverse pattern of the reference pattern in a second block includes providing a substrate having a silicon thin film; positioning the first block of the laser mask over a portion of the silicon film and irradiating a first laser beam through the first block; and moving either the laser mask or the substrate to position the second block of the laser mask over the portion of the silicon film and irradiating a second laser beam through the second block.
Abstract:
A method for manufacturing a boride single crystal is provided, wherein an initial melt region formed from an ingredient powder including an excessive content of boron than a stoichiometric composition of a boride is provided at one end in the longitudinal direction of a feed rod formed from a ingredient powder containing boron and a metallic element that constitute the boride, the initial melt region is heated to melt so as to form a molten zone, and the molten zone is moved toward the other end of the feed rod along the longitudinal direction, so as to grow the boride single crystal in a portion of the feed rod that the molten zone has passed. A substrate formed by the manufacturing method and particularly suitable for epitaxial growing a semiconductor layer such as a GaN-based semiconductor layer thereon is also provided.
Abstract:
The present invention provides a method for producing a single crystal by pulling a single crystal from a raw material melt in a chamber in accordance with Czochralski method, comprising pulling a single crystal having a defect-free region which is outside an OSF region to occur in a ring shape in the radial direction and which interstitial-type and vacancy-type defects do not exist in, wherein the pulling of the single crystal is performed with being controlled so that an average of cooling rate in passing through a temperature region of the melt point of the single crystal to 950° C. is in the range of 0.96° C./min or more and so that an average of cooling rate in passing through a temperature region of 1150° C. to 1080° C. is in the range of 0.88° C./min or more and so that an average of cooling rate in passing through a temperature region of 1050° C. to 950° C. is in the range of 0.71° C./min or more. Thereby, production margin in pulling a single crystal having a defect-free region can be considerably enlarged and therefore there can be provided a method for producing a single crystal by which production yield and productivity of the crystal having the defect-free region can be considerably improved.
Abstract:
Improved contaminant removal from alkaline- or alkali-earth metal fluoride crystal growth material can be obtained by coprecipitating an alkaline- or alkali-earth metal fluoride with a scavenging agent during synthesis of the fluoride growth material. The coprecipitation of the alkaline- or alkali-earth metal fluoride and scavenging agent can be performed using at least one of chloride, nitrate, hydroxide and carbonate salts of the alkaline- or alkali-earth metal fluoride and scavenging agent. This provides a more intimate mixture or dispersion of the scavenging agent in solid solution or as a mechanical mixture with the alkaline- or alkali-earth metal fluoride for improved outgassing and fewer trapped impurities, leading to improved radiation hardness and bulk absorption.
Abstract:
An apparatus (1) is provided for manufacturing a single crystal rod (2) from a poly crystal feed rod (3), said apparatus (1) comprising a closed chamber (4), at which chamber (4) the feed rod (3) is located, said chamber (4) comprising an annular energy supply (5) arranged around the feed rod (3) for melting off the one end (23) of the rod for providing single crystals, said apparatus comprising first moving means (6) for axial movement of the feed rod (3) and second moving means (7) for a rotating relative movement between the feed rod (3) and the annular energy supply (5). The apparatus (1) comprises a monitoring system (8) for recording the distance between the surface (9) of the feed rod (3), and an annular inwardly radially facing reference face associated with the energy supply (5), and third moving means (10) for regulating the distance. Hereby an apparatus and a method are accomplished that enable use of irregular feed rods that assume other shapes than the optimal cylindrical shape and also enable use of curved cylindrical an elliptical rods with irregular surfaces.
Abstract:
A heat shield and a crystal growth equipment are provided, in which the length-adjustable and hybrid-angle heat shield is provided for the crystal growth equipments. The heat shield is adapted for not only guiding the inert gas flow but also speeding up the flow rate of the gas and the cooling rate of the crystal so as to raise the axial temperature gradient at the solid-molten interface, the growth rate of the crystal and the productivity. The heat shield further can also reduce the possibility of microdefect nucleation to improve the quality of crystal at the same time. In addition, the length of heat shield can be adjusted according to the distance between the heat shield and the semiconductor material melt in different crucibles in case that the crucibles are made by different factories. This can reduce the cost of the heat shield manufacturing.
Abstract:
Means for supplying raw material in additional charging or recharging of solid granular raw material into molten material in the crucible, comprises a raw material supply tube to be filled with said material, a metallic support member which runs through the inside of the tube, connects with the bottom lid, and serves for descending the lid and for ascending the tube and the lid, and a configuration avoiding metallic contamination, whereby the lower-end aperture of the tube is opened for charging said material therein into the crucible in uniform circumferential distribution and in large quantity, thus achieving efficient supply operation to be widely applied for growing silicon single crystals.
Abstract:
A semiconductor film formation method allowing a single-crystal semiconductor film to be formed at a desired position on a substrate with reliability is disclosed. After preparing the substrate having a non-single-crystal semiconductor film formed thereon and an optical mask having a predetermined pattern, a projection area of the optical mask is relatively positioned at the desired position on the substrate. Thereafter, the desired position of the non-single-crystal semiconductor film is irradiated with laser light through the optical mask to change an irradiated portion of the non-single-crystal semiconductor film to the single-crystal semiconductor film. Then, an insulation film is formed on at least the single-crystal semiconductor film.
Abstract:
Methods and apparatus for concurrent growth of multiple crystalline ribbons from a single crucible employ meniscus shapers to facilitate continuous growth of discrete and substantially flat crystalline ribbons having controlled width.