A method for the production of a graphene layer structure, the method comprising providing a substrate on a heated susceptor in a reaction chamber, the chamber having a plurality of cooled inlets arranged so that, in use, the inlets are distributed across the substrate and have a constant separation from the substrate, rotating the heated susceptor at a rotation rate of at least 300 rpm, supplying a flow comprising a precursor compound through the inlets and into the reaction chamber to thereby decompose the precursor compound and form graphene on the substrate, wherein the inlets are cooled to less than 100° C., preferably 50 to 60° C., and the susceptor is heated to a temperature of at least 50° C. in excess of a decomposition temperature of the precursor, wherein the constant separation is at least 12 cm and preferably from 12 to 20 cm.

A method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 10.sup.7 cm.sup.−2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

A film deposition method includes depositing an amorphous silicon film in a substrate under a process condition. The process condition includes supplying SiH.sub.4 gas into a processing chamber in which the substrate is placed. The process condition includes setting a temperature in the processing chamber to be in a range of greater than or equal to 300° C. and less than or equal to 440° C. The process condition includes setting a pressure of the processing chamber to be in a range of greater than or equal to 10 Torr and less than or equal to 100 Torr.

A film deposition method includes depositing an amorphous silicon film in a substrate under a process condition. The process condition includes supplying SiH.sub.4 gas into a processing chamber in which the substrate is placed. The process condition includes setting a temperature in the processing chamber to be in a range of greater than or equal to 300° C. and less than or equal to 440° C. The process condition includes setting a pressure of the processing chamber to be in a range of greater than or equal to 10 Torr and less than or equal to 100 Torr.

Provided is a process of baking the inside of a reaction chamber in a re-operation preparation process of the reaction chamber in which epitaxial growth is performed on a wafer. The process of baking the inside of the reaction chamber in the re-operation preparation process of the reaction chamber in which epitaxial growth is performed on the wafer includes rising an inner temperature of the reaction chamber in stages according to a time and introducing a hydrogen gas to upper and lower sides of a susceptor through a main valve and a slit valve, which are provided in a side surface of the reaction chamber. Thus, since power of a heating source for transmitting heat into the reaction chamber increases in stages, an atmosphere in the reaction chamber may be unstable to allow stagnant moisture and contaminants to flow, thereby effectively discharging the moisture and contaminants.

Provided is a process of baking the inside of a reaction chamber in a re-operation preparation process of the reaction chamber in which epitaxial growth is performed on a wafer. The process of baking the inside of the reaction chamber in the re-operation preparation process of the reaction chamber in which epitaxial growth is performed on the wafer includes rising an inner temperature of the reaction chamber in stages according to a time and introducing a hydrogen gas to upper and lower sides of a susceptor through a main valve and a slit valve, which are provided in a side surface of the reaction chamber. Thus, since power of a heating source for transmitting heat into the reaction chamber increases in stages, an atmosphere in the reaction chamber may be unstable to allow stagnant moisture and contaminants to flow, thereby effectively discharging the moisture and contaminants.

A crucible device includes a heating chamber, at least a first crucible in which a first crystal is growable, and at least a second crucible in which a second crystal is growable. The first crucible and the second crucible are arranged within the heating chamber spaced apart from each other along a horizontal and vertical and any orientational direction. The crucible device further comprises a heating system arranged within the heating chamber, wherein the heating system is configured for adjusting a temperature along the horizontal and vertical and any orientational directions.

A crucible device includes a heating chamber, at least a first crucible in which a first crystal is growable, and at least a second crucible in which a second crystal is growable. The first crucible and the second crucible are arranged within the heating chamber spaced apart from each other along a horizontal and vertical and any orientational direction. The crucible device further comprises a heating system arranged within the heating chamber, wherein the heating system is configured for adjusting a temperature along the horizontal and vertical and any orientational directions.

A vapor phase growth system includes a process chamber that includes a susceptor lifting mechanism that raises and lowers the susceptor between a first position and a second position. With the susceptor in the first position, the top surface of the susceptor is above the bottom surface of the preheating ring, and a source gas distribution space with a predetermined height dimension is secured between the top surface of the susceptor and the bottom surface of a ceiling plate of the reaction vessel body. With the susceptor in the second position, the top surface of the susceptor is located below the bottom surface of a preheating ring, and a substrate loading/unloading space, which has a greater height dimension than that of the source gas distribution space, is secured between the top surface of the susceptor and the bottom surface of the preheating ring.

A vapor phase growth system includes a process chamber that includes a susceptor lifting mechanism that raises and lowers the susceptor between a first position and a second position. With the susceptor in the first position, the top surface of the susceptor is above the bottom surface of the preheating ring, and a source gas distribution space with a predetermined height dimension is secured between the top surface of the susceptor and the bottom surface of a ceiling plate of the reaction vessel body. With the susceptor in the second position, the top surface of the susceptor is located below the bottom surface of a preheating ring, and a substrate loading/unloading space, which has a greater height dimension than that of the source gas distribution space, is secured between the top surface of the susceptor and the bottom surface of the preheating ring.