A vapor phase epitaxy method of growing a III-V layer with a doping that changes from a first conductivity type to a second conductivity type on a surface of a substrate or a preceding layer in a reaction chamber from the vapor phase from an epitaxial gas flow comprising a carrier gas, at least one first precursor for an element from main group III, and at least one second precursor for an element from main group V, wherein when a first growth height is reached, a first initial doping level of the first conductivity type is set by means of a ratio of a first mass flow of the first precursor to a second mass flow of the second precursor, then the first initial doping level is reduced to a second initial doping level of the first or low second conductivity type.

A Metalorganic chemical vapor phase epitaxy or vapor phase deposition apparatus, having a first gas source system, a reactor, an exhaust gas system, and a control unit, wherein the first gas source system has a carrier gas source, a bubbler with an organometallic starting compound, and a first supply section leading to the reactor either directly or through a first control valve, the carrier gas source is connected to an inlet of the bubbler through a first mass flow controller by a second supply section, an outlet of the bubbler is connected to the first supply section, and the carrier gas source is connected to the first supply section through a second mass flow controller by a third supply section, the first supply section is connected to an inlet of the reactor through a third mass flow controller.

According to the present invention, there is provided a group III nitride semiconductor substrate (free-standing substrate 30) that is formed of group III nitride semiconductor crystals. Both exposed first and second main surfaces in a relationship of top and bottom are semipolar planes. A variation coefficient of an emission wavelength of each of the first and second main surfaces, which is calculated by dividing a standard deviation of an emission wavelength by an average value of the emission wavelength, is 0.05% or less in photoluminescence (PL) measurement in which mapping is performed in units of an area of 1 mm.sup.2 by emitting helium-cadmium (He—Cd) laser, which has a wavelength of 325 nm and an output of 10 mW or more and 40 mW or less, at room temperature. In a case where devices are manufactured over the free-standing substrate 30, variations in quality among the devices are suppressed.

Hydride phase vapor epitaxy (HVPE) growth apparatus, methods and materials and structures grown thereby. An HVPE reactor includes generation, accumulation, and growth zones. A source material for growth of indium nitride is generated and collected inside the reactor. A first reactive gas reacts with an indium source inside the generation zone to produce a first gas product having an indium-containing compound. The first gas product is cooled and condenses into a liquid or solid condensate or source material having an indium-containing compound. The source material is collected in the accumulation zone. Vapor or gas resulting from evaporation of the condensate forms a second gas product, which reacts with a second reactive gas in the growth zone for growth of indium nitride.

A method and apparatus for reducing cool-down times within a cool-down chamber are described herein. The method and apparatus include a process chamber, a transfer chamber, a dual-handled transfer robot within the transfer chamber, and a cool-down chamber. The dual-handled transfer robot it utilized to transfer a substrate between the process chamber and the cool-down chamber. The amount of time the substrate is disposed on the dual-handled transfer robot before being moved into the cool-down chamber is multiplied by a correction factor and subtracted from an original cool down time to achieve an adjusted cool down time. The adjusted cool down time is determined separately for each substrate being cooled within the cool-down chamber.

A method and apparatus for reducing cool-down times within a cool-down chamber are described herein. The method and apparatus include a process chamber, a transfer chamber, a dual-handled transfer robot within the transfer chamber, and a cool-down chamber. The dual-handled transfer robot it utilized to transfer a substrate between the process chamber and the cool-down chamber. The amount of time the substrate is disposed on the dual-handled transfer robot before being moved into the cool-down chamber is multiplied by a correction factor and subtracted from an original cool down time to achieve an adjusted cool down time. The adjusted cool down time is determined separately for each substrate being cooled within the cool-down chamber.

A method for producing an aluminium nitride (AlN)-based layer on a structure with the basis of silicon (Si) or with the basis of a III-V material, may include several deposition cycles performed in a plasma reactor comprising a reaction chamber inside which is disposed a substrate having the structure. Each deposition cycle may include at least the following: deposition of aluminium-based species on an exposed surface of the structure, the deposition including at least one injection into the reaction chamber of an aluminium (Al)-based precursor; and nitridation of the exposed surface of the structure, the nitridation including at least one injection into the reaction chamber of a nitrogen (N)-based precursor and the formation in the reaction chamber of a nitrogen-based plasma. During the formation of the nitrogen-based plasma, a non-zero polarisation voltage V.sub.bias_.sub.substrate may be applied to the substrate.

A method of selectively controlling materials structure in solution based chemical synthesis and deposition of materials by controlling input energy from pulsed energy source includes determining solution conditions, searching and/or determining energy barrier(s) of a desired materials structure formation, applying precursor solution with selected solution condition onto a substrate, and applying determined input energy from a pulsed energy source with a selected condition to the substrate, thereby nucleating and growing the crystal.

A method of selectively controlling materials structure in solution based chemical synthesis and deposition of materials by controlling input energy from pulsed energy source includes determining solution conditions, searching and/or determining energy barrier(s) of a desired materials structure formation, applying precursor solution with selected solution condition onto a substrate, and applying determined input energy from a pulsed energy source with a selected condition to the substrate, thereby nucleating and growing the crystal.

A method for forming a laterally-grown group III metal nitride crystal includes providing a substrate, the substrate including one of sapphire, silicon carbide, gallium arsenide, silicon, germanium, a silicon-germanium alloy, MgAl.sub.2O.sub.4 spinel, ZnO, ZrB.sub.2, BP, InP, AlON, ScAlMgO.sub.4, YFeZnO.sub.4, MgO, Fe.sub.2NiO.sub.4, LiGa.sub.5O.sub.8, Na.sub.2MoO.sub.4, Na.sub.2WO.sub.4, In.sub.2CdO.sub.4, lithium aluminate (LiAlO.sub.2), LiGaO.sub.2, Ca.sub.8La.sub.2(PO.sub.4).sub.6O.sub.2, gallium nitride, or aluminum nitride (AlN), forming a pattern on the substrate, the pattern comprising growth centers having a minimum dimension between 1 micrometer and 100 micrometers, and being characterized by at least one pitch dimension between 20 micrometers and 5 millimeters, growing a group III metal nitride from the pattern of growth centers vertically and laterally, and removing the laterally-grown group III metal nitride layer from the substrate. A laterally-grown group III metal nitride layer coalesces, leaving an air gap between the laterally-grown group III metal nitride layer and the substrate or a mask thereupon.