The present invention relates to a vacuum evacuation system used to evacuate a processing gas from one or more process chambers for use in, for example, a semiconductor-device manufacturing apparatus. The vacuum evacuation system is a vacuum apparatus for evacuating a gas from a plurality of process chambers (1). The vacuum evacuation system includes a plurality of first vacuum pumps (5) coupled to the plurality of process chambers (1) respectively, a collecting pipe (7) coupled to the plurality of first vacuum pumps (5), and a second vacuum pump (8) coupled to the collecting pipe (7).

A silicon carbide epitaxial substrate includes a silicon carbide single-crystal substrate of one conductivity type, a first silicon carbide layer of the above-mentioned one conductivity type, a second silicon carbide layer of the above-mentioned one conductivity type, and a third silicon carbide layer of the above-mentioned one conductivity type. The silicon carbide single-crystal substrate has first impurity concentration. The first silicon carbide layer is provided on the silicon carbide single-crystal substrate, and has second impurity concentration that is lower than the first impurity concentration. The second silicon carbide layer is provided on the first silicon carbide layer, and has third impurity concentration that is higher than the first impurity concentration. The third silicon carbide layer is provided on the second silicon carbide layer, and has fourth impurity concentration that is lower than the second impurity concentration.

Provided is a processing container formed of a reaction tube and a manifold that supports the reaction tube from below, and adapted to process a substrate inside, a nozzle adapted to supply a processing gas to the substrate, and a connecting portion adapted to erect the nozzle inside the processing container. The connecting portion includes (1) a fixing portion formed of a cylindrical portion inserted into an introduction portion provided at the manifold, and a flange plate formed at an end portion of the cylindrical portion, and (2) a detachable portion formed of an elbow engaged with the flange plate, and an installation portion in which the nozzle is installed.

A semiconductor wafer is provided, which has a silicon wafer, a reaction suppressing layer, a stress generating layer and an active layer, the silicon wafer, the reaction suppressing layer, the stress generating layer and the active layer being disposed in an order of the silicon wafer, the reaction suppressing layer, the stress generating layer and the active layer, where the reaction suppressing layer is a nitride crystal layer that suppresses reaction between silicon atoms and group-III atoms, the stress generating layer is a nitride crystal layer that generates compressive stress, the active layer is a nitride crystal layer in which an electronic device is formed, and the semiconductor wafer further has, between the silicon wafer and the reaction suppressing layer, a SiAlN layer having silicon atoms, aluminum atoms and nitrogen atoms as main constituent atoms.

Methods for seam-less gapfill comprising forming a flowable film by PECVD, annealing the flowable film with a reactive anneal to form an annealed film and curing the flowable film or annealed film to solidify the film. The flowable film can be formed using a higher order silane and plasma. The reactive anneal may use a silane or higher order silane. A UV cure, or other cure, can be used to solidify the flowable film or the annealed film.

There is provided a technique that includes: substrate mounting plate where substrates are arranged circumferentially; rotator rotating the substrate mounting plate; gas supply structure disposed above the substrate mounting plate from center to outer periphery thereof; gas supplier including the gas supply structure and controlling supply amount of gas supplied from the gas supply structure; gas exhaust structure installed above the substrate mounting plate at downstream side of the gas supply structure in rotation direction; gas exhauster including the gas exhaust structure and controlling exhaust amount of gas exhausted from the gas exhaust structure; and gas main component amount controller including the gas supplier and the gas exhauster and controlling gas main component amount in the gas supplied from the gas supply structure to the substrates and the gas main component amount in the gas supplied to the substrates from the center to the outer periphery of the mounting plate.

A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 110.sup.15 cm.sup.3 and not more than 510.sup.16 cm.sup.3. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a groove 80 extending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.

A method for producing a SiC epitaxial wafer using an apparatus including a mounting plate having a recessed accommodation portion and a satellite disposed in the recessed accommodation portion, and configured so that a SiC substrate is placed on an upper surface thereof. The method includes supplying a dopant carrier gas to an outer circumference of the SiC epitaxial wafer from between the recessed accommodation portion and the satellite.

A method of manufacturing an optical semiconductor element includes: stacking a plurality of compound semiconductor layers on a first substrate containing a compound semiconductor; dividing the first substrate into small pieces; forming terraces, grooves, walls, and a first mesa for a waveguide on a second substrate containing silicon; jointing at least one small piece to the second substrate after the forming; wet-etching the first substrate so as to expose the compound semiconductor layers after the jointing; and forming a second mesa opposite to the first mesa from the compound semiconductor layers; wherein the grooves are formed on both sides of the first mesa, the terraces are formed on both sides of the first mesa and the grooves, and the walls are arranged in an extending direction of each groove.

A supply part includes a first partition, a second partition under the first partition, a third partition under the second partition, a first flow path between the first partition and the second partition allowing a first gas to be introduced therein, a second flow path between the second partition and the third partition allowing a second gas to be introduced therein, a first piping extending from the second partition to reach below the third partition and being communicated with the first flow path, a second piping extending from the third partition to reach below the third partition and being communicated with the second flow path, and a convex portion provided on an outer circumferential surface of the first piping or an inner circumferential surface of the second piping protruding from one of the outer circumferential surface and the inner circumferential surface toward the other one.