Abstract: Apparatus and methods for controlling gas flows in a HVPE reactor. Gas flows may be controlled by a gas focusing element. Gas injection and gas collection tubes are positioned within an outer tube and are separated from each other to define a space there between. A gas, such as HCl gas, flows over the outer surfaces of the injection and collection tubes to contain gases within the space as they flow from the injection tube to the collection tube and over a seed upon which group III nitride materials are grown. Gas flows may also be controlled by a multi-tube structure that separates gases until they reach a grown zone. A multi-tube structure may include four tubes, which separate flows of a halide reactive gas, a reaction product that flows with a carrier gas, and ammonia.

Abstract: HVPE reactors and methods for growth of p-type group III nitride materials including p-GaN. A reaction product such as gallium chloride is delivered to a growth zone inside of a HVPE reactor by a carrier gas such as Argon. The gallium chloride reacts with a reactive gas such as ammonia in the growth zone in the presence of a magnesium-containing gas to grow p-type group III nitride materials. The source of magnesium is an external, non-metallic compound source such as Cp2Mg.

Abstract: HVPE method for simultaneously fabricating multiple Group III nitride semiconductor structures during a single reactor run. A HVPE reactor includes a reactor tube, a growth zone, a heating element and a plurality of gas blocks. A substrate holder is capable of holding multiple substrates and can be a single or multi-level substrate holder. The gas delivery blocks are independently controllable. Gas flows from the delivery blocks are mixed to provide a substantially uniform gas environment within the growth zone. The substrate holder can be controlled, e.g., rotated and/or tilted, for uniform material growth. Multiple Group III nitride semiconductor structures can be grown on each substrate during a single fabrication run of the HVPE reactor. Growth on different substrates is substantially uniform and can be performed on larger area substrates, such as 3-12? substrates.